The CFS, UsOpt, and opt.Uint fields added on this branch used
omitempty, which is silently ignored for structs by encoding/json.
Switch to omitzero (Go 1.24) consistent with the fix in elastic#288.

Refactor omitzero_test.go to table-driven style with exact key
equality via assert.Equal instead of Contains/NotContains.

…v2 CPU CFS data (#49098)

Bumps the elastic-agent-system-metrics dependency to [v0.14.3](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.3), [v0.14.2](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.2) also included.

### What's Changed
* Add Zswap Metrics by @orestisfl in elastic/elastic-agent-system-metrics#279
* PULL_REQUEST_TEMPLATE: Remove reference to non-existant CHANGELOG.md by @orestisfl in elastic/elastic-agent-system-metrics#286
* fix: remove shared context timeout from matrix tests by @orestisfl in elastic/elastic-agent-system-metrics#285
* Enable modernize linter and apply suggestions by @orestisfl in elastic/elastic-agent-system-metrics#287
* Use json omitzero for struct-typed fields in cgroup structs by @orestisfl in elastic/elastic-agent-system-metrics#288
* [cgv2] Add CPU CFS quota, period, and weight metrics by @orestisfl in elastic/elastic-agent-system-metrics#281
* Add missing zswap debug metrics by @orestisfl in elastic/elastic-agent-system-metrics#289

## Disruptive User Impact

None. New features.

## How to test this PR locally

1. Build metricbeat from the branch:

```bash
cd metricbeat
mage build
```

2. Create a test config file `metricbeat.test.yml`:

```yaml
metricbeat.modules:
  - module: system
    period: 5s
    metricsets:
      - memory
      - process
    process.include_top_n:
      by_cpu: 5
      by_memory: 5

output.console:
  pretty: true

logging.level: debug
```

3. Run metricbeat:

```bash
./metricbeat -e -c metricbeat.test.yml
```

4. Verify zswap memory metrics appear in the output (requires Linux with zswap enabled -- check with `cat /sys/module/zswap/parameters/enabled`):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "memory") | .system.memory.zswap'
```

Expected output (values will vary):

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976
}
```

5. To also verify the `zswap.debug.*` fields (requires debugfs access), grant the binary the `cap_dac_read_search` capability:

```bash
sudo setcap cap_dac_read_search=+ep metricbeat
```

Then re-run. Expected output with debug fields:

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976,
  "debug": {
    "decompress_fail": 0,
    "pool_limit_hit": 0,
    "pool_total_size": 950353920,
    "reject_alloc_fail": 0,
    "reject_compress_fail": 0,
    "reject_compress_poor": 0,
    "reject_kmemcache_fail": 0,
    "reject_reclaim_fail": 0,
    "stored_incompressible_pages": 16779,
    "stored_pages": 931031,
    "written_back_pages": 29111
  }
}
```

6. Verify `cfs.weight` appears in process cgroup metrics (requires cgroupsv2):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "process") | .system.process.cgroup.cpu.cfs.weight // empty'
```

7. Run unit tests:

```bash
cd metricbeat
go test ./module/system/...
```

…v2 CPU CFS data (#49098)

Bumps the elastic-agent-system-metrics dependency to [v0.14.3](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.3), [v0.14.2](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.2) also included.

### What's Changed
* Add Zswap Metrics by @orestisfl in elastic/elastic-agent-system-metrics#279
* PULL_REQUEST_TEMPLATE: Remove reference to non-existant CHANGELOG.md by @orestisfl in elastic/elastic-agent-system-metrics#286
* fix: remove shared context timeout from matrix tests by @orestisfl in elastic/elastic-agent-system-metrics#285
* Enable modernize linter and apply suggestions by @orestisfl in elastic/elastic-agent-system-metrics#287
* Use json omitzero for struct-typed fields in cgroup structs by @orestisfl in elastic/elastic-agent-system-metrics#288
* [cgv2] Add CPU CFS quota, period, and weight metrics by @orestisfl in elastic/elastic-agent-system-metrics#281
* Add missing zswap debug metrics by @orestisfl in elastic/elastic-agent-system-metrics#289

## Disruptive User Impact

None. New features.

## How to test this PR locally

1. Build metricbeat from the branch:

```bash
cd metricbeat
mage build
```

2. Create a test config file `metricbeat.test.yml`:

```yaml
metricbeat.modules:
  - module: system
    period: 5s
    metricsets:
      - memory
      - process
    process.include_top_n:
      by_cpu: 5
      by_memory: 5

output.console:
  pretty: true

logging.level: debug
```

3. Run metricbeat:

```bash
./metricbeat -e -c metricbeat.test.yml
```

4. Verify zswap memory metrics appear in the output (requires Linux with zswap enabled -- check with `cat /sys/module/zswap/parameters/enabled`):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "memory") | .system.memory.zswap'
```

Expected output (values will vary):

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976
}
```

5. To also verify the `zswap.debug.*` fields (requires debugfs access), grant the binary the `cap_dac_read_search` capability:

```bash
sudo setcap cap_dac_read_search=+ep metricbeat
```

Then re-run. Expected output with debug fields:

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976,
  "debug": {
    "decompress_fail": 0,
    "pool_limit_hit": 0,
    "pool_total_size": 950353920,
    "reject_alloc_fail": 0,
    "reject_compress_fail": 0,
    "reject_compress_poor": 0,
    "reject_kmemcache_fail": 0,
    "reject_reclaim_fail": 0,
    "stored_incompressible_pages": 16779,
    "stored_pages": 931031,
    "written_back_pages": 29111
  }
}
```

6. Verify `cfs.weight` appears in process cgroup metrics (requires cgroupsv2):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "process") | .system.process.cgroup.cpu.cfs.weight // empty'
```

7. Run unit tests:

```bash
cd metricbeat
go test ./module/system/...
```

(cherry picked from commit eeabffa)

# Conflicts:
#	metricbeat/module/system/fields.go

…v2 CPU CFS data (#49098)

Bumps the elastic-agent-system-metrics dependency to [v0.14.3](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.3), [v0.14.2](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.2) also included.

### What's Changed
* Add Zswap Metrics by @orestisfl in elastic/elastic-agent-system-metrics#279
* PULL_REQUEST_TEMPLATE: Remove reference to non-existant CHANGELOG.md by @orestisfl in elastic/elastic-agent-system-metrics#286
* fix: remove shared context timeout from matrix tests by @orestisfl in elastic/elastic-agent-system-metrics#285
* Enable modernize linter and apply suggestions by @orestisfl in elastic/elastic-agent-system-metrics#287
* Use json omitzero for struct-typed fields in cgroup structs by @orestisfl in elastic/elastic-agent-system-metrics#288
* [cgv2] Add CPU CFS quota, period, and weight metrics by @orestisfl in elastic/elastic-agent-system-metrics#281
* Add missing zswap debug metrics by @orestisfl in elastic/elastic-agent-system-metrics#289

## Disruptive User Impact

None. New features.

## How to test this PR locally

1. Build metricbeat from the branch:

```bash
cd metricbeat
mage build
```

2. Create a test config file `metricbeat.test.yml`:

```yaml
metricbeat.modules:
  - module: system
    period: 5s
    metricsets:
      - memory
      - process
    process.include_top_n:
      by_cpu: 5
      by_memory: 5

output.console:
  pretty: true

logging.level: debug
```

3. Run metricbeat:

```bash
./metricbeat -e -c metricbeat.test.yml
```

4. Verify zswap memory metrics appear in the output (requires Linux with zswap enabled -- check with `cat /sys/module/zswap/parameters/enabled`):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "memory") | .system.memory.zswap'
```

Expected output (values will vary):

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976
}
```

5. To also verify the `zswap.debug.*` fields (requires debugfs access), grant the binary the `cap_dac_read_search` capability:

```bash
sudo setcap cap_dac_read_search=+ep metricbeat
```

Then re-run. Expected output with debug fields:

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976,
  "debug": {
    "decompress_fail": 0,
    "pool_limit_hit": 0,
    "pool_total_size": 950353920,
    "reject_alloc_fail": 0,
    "reject_compress_fail": 0,
    "reject_compress_poor": 0,
    "reject_kmemcache_fail": 0,
    "reject_reclaim_fail": 0,
    "stored_incompressible_pages": 16779,
    "stored_pages": 931031,
    "written_back_pages": 29111
  }
}
```

6. Verify `cfs.weight` appears in process cgroup metrics (requires cgroupsv2):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "process") | .system.process.cgroup.cpu.cfs.weight // empty'
```

7. Run unit tests:

```bash
cd metricbeat
go test ./module/system/...
```

(cherry picked from commit eeabffa)

…v2 CPU CFS data (#49098)

Bumps the elastic-agent-system-metrics dependency to [v0.14.3](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.3), [v0.14.2](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.2) also included.

### What's Changed
* Add Zswap Metrics by @orestisfl in elastic/elastic-agent-system-metrics#279
* PULL_REQUEST_TEMPLATE: Remove reference to non-existant CHANGELOG.md by @orestisfl in elastic/elastic-agent-system-metrics#286
* fix: remove shared context timeout from matrix tests by @orestisfl in elastic/elastic-agent-system-metrics#285
* Enable modernize linter and apply suggestions by @orestisfl in elastic/elastic-agent-system-metrics#287
* Use json omitzero for struct-typed fields in cgroup structs by @orestisfl in elastic/elastic-agent-system-metrics#288
* [cgv2] Add CPU CFS quota, period, and weight metrics by @orestisfl in elastic/elastic-agent-system-metrics#281
* Add missing zswap debug metrics by @orestisfl in elastic/elastic-agent-system-metrics#289

## Disruptive User Impact

None. New features.

## How to test this PR locally

1. Build metricbeat from the branch:

```bash
cd metricbeat
mage build
```

2. Create a test config file `metricbeat.test.yml`:

```yaml
metricbeat.modules:
  - module: system
    period: 5s
    metricsets:
      - memory
      - process
    process.include_top_n:
      by_cpu: 5
      by_memory: 5

output.console:
  pretty: true

logging.level: debug
```

3. Run metricbeat:

```bash
./metricbeat -e -c metricbeat.test.yml
```

4. Verify zswap memory metrics appear in the output (requires Linux with zswap enabled -- check with `cat /sys/module/zswap/parameters/enabled`):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "memory") | .system.memory.zswap'
```

Expected output (values will vary):

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976
}
```

5. To also verify the `zswap.debug.*` fields (requires debugfs access), grant the binary the `cap_dac_read_search` capability:

```bash
sudo setcap cap_dac_read_search=+ep metricbeat
```

Then re-run. Expected output with debug fields:

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976,
  "debug": {
    "decompress_fail": 0,
    "pool_limit_hit": 0,
    "pool_total_size": 950353920,
    "reject_alloc_fail": 0,
    "reject_compress_fail": 0,
    "reject_compress_poor": 0,
    "reject_kmemcache_fail": 0,
    "reject_reclaim_fail": 0,
    "stored_incompressible_pages": 16779,
    "stored_pages": 931031,
    "written_back_pages": 29111
  }
}
```

6. Verify `cfs.weight` appears in process cgroup metrics (requires cgroupsv2):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "process") | .system.process.cgroup.cpu.cfs.weight // empty'
```

7. Run unit tests:

```bash
cd metricbeat
go test ./module/system/...
```

(cherry picked from commit eeabffa)

…v2 CPU CFS data (#49098) (#49399)

Bumps the elastic-agent-system-metrics dependency to [v0.14.3](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.3), [v0.14.2](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.2) also included.

### What's Changed
* Add Zswap Metrics by @orestisfl in elastic/elastic-agent-system-metrics#279
* PULL_REQUEST_TEMPLATE: Remove reference to non-existant CHANGELOG.md by @orestisfl in elastic/elastic-agent-system-metrics#286
* fix: remove shared context timeout from matrix tests by @orestisfl in elastic/elastic-agent-system-metrics#285
* Enable modernize linter and apply suggestions by @orestisfl in elastic/elastic-agent-system-metrics#287
* Use json omitzero for struct-typed fields in cgroup structs by @orestisfl in elastic/elastic-agent-system-metrics#288
* [cgv2] Add CPU CFS quota, period, and weight metrics by @orestisfl in elastic/elastic-agent-system-metrics#281
* Add missing zswap debug metrics by @orestisfl in elastic/elastic-agent-system-metrics#289

## Disruptive User Impact

None. New features.

## How to test this PR locally

1. Build metricbeat from the branch:

```bash
cd metricbeat
mage build
```

2. Create a test config file `metricbeat.test.yml`:

```yaml
metricbeat.modules:
  - module: system
    period: 5s
    metricsets:
      - memory
      - process
    process.include_top_n:
      by_cpu: 5
      by_memory: 5

output.console:
  pretty: true

logging.level: debug
```

3. Run metricbeat:

```bash
./metricbeat -e -c metricbeat.test.yml
```

4. Verify zswap memory metrics appear in the output (requires Linux with zswap enabled -- check with `cat /sys/module/zswap/parameters/enabled`):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "memory") | .system.memory.zswap'
```

Expected output (values will vary):

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976
}
```

5. To also verify the `zswap.debug.*` fields (requires debugfs access), grant the binary the `cap_dac_read_search` capability:

```bash
sudo setcap cap_dac_read_search=+ep metricbeat
```

Then re-run. Expected output with debug fields:

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976,
  "debug": {
    "decompress_fail": 0,
    "pool_limit_hit": 0,
    "pool_total_size": 950353920,
    "reject_alloc_fail": 0,
    "reject_compress_fail": 0,
    "reject_compress_poor": 0,
    "reject_kmemcache_fail": 0,
    "reject_reclaim_fail": 0,
    "stored_incompressible_pages": 16779,
    "stored_pages": 931031,
    "written_back_pages": 29111
  }
}
```

6. Verify `cfs.weight` appears in process cgroup metrics (requires cgroupsv2):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "process") | .system.process.cgroup.cpu.cfs.weight // empty'
```

7. Run unit tests:

```bash
cd metricbeat
go test ./module/system/...
```

(cherry picked from commit eeabffa)

Co-authored-by: Orestis Floros <orestis.floros@elastic.co>

…v2 CPU CFS data (#49098) (#49400)

Bumps the elastic-agent-system-metrics dependency to [v0.14.3](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.3), [v0.14.2](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.2) also included.

### What's Changed
* Add Zswap Metrics by @orestisfl in elastic/elastic-agent-system-metrics#279
* PULL_REQUEST_TEMPLATE: Remove reference to non-existant CHANGELOG.md by @orestisfl in elastic/elastic-agent-system-metrics#286
* fix: remove shared context timeout from matrix tests by @orestisfl in elastic/elastic-agent-system-metrics#285
* Enable modernize linter and apply suggestions by @orestisfl in elastic/elastic-agent-system-metrics#287
* Use json omitzero for struct-typed fields in cgroup structs by @orestisfl in elastic/elastic-agent-system-metrics#288
* [cgv2] Add CPU CFS quota, period, and weight metrics by @orestisfl in elastic/elastic-agent-system-metrics#281
* Add missing zswap debug metrics by @orestisfl in elastic/elastic-agent-system-metrics#289

## Disruptive User Impact

None. New features.

## How to test this PR locally

1. Build metricbeat from the branch:

```bash
cd metricbeat
mage build
```

2. Create a test config file `metricbeat.test.yml`:

```yaml
metricbeat.modules:
  - module: system
    period: 5s
    metricsets:
      - memory
      - process
    process.include_top_n:
      by_cpu: 5
      by_memory: 5

output.console:
  pretty: true

logging.level: debug
```

3. Run metricbeat:

```bash
./metricbeat -e -c metricbeat.test.yml
```

4. Verify zswap memory metrics appear in the output (requires Linux with zswap enabled -- check with `cat /sys/module/zswap/parameters/enabled`):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "memory") | .system.memory.zswap'
```

Expected output (values will vary):

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976
}
```

5. To also verify the `zswap.debug.*` fields (requires debugfs access), grant the binary the `cap_dac_read_search` capability:

```bash
sudo setcap cap_dac_read_search=+ep metricbeat
```

Then re-run. Expected output with debug fields:

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976,
  "debug": {
    "decompress_fail": 0,
    "pool_limit_hit": 0,
    "pool_total_size": 950353920,
    "reject_alloc_fail": 0,
    "reject_compress_fail": 0,
    "reject_compress_poor": 0,
    "reject_kmemcache_fail": 0,
    "reject_reclaim_fail": 0,
    "stored_incompressible_pages": 16779,
    "stored_pages": 931031,
    "written_back_pages": 29111
  }
}
```

6. Verify `cfs.weight` appears in process cgroup metrics (requires cgroupsv2):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "process") | .system.process.cgroup.cpu.cfs.weight // empty'
```

7. Run unit tests:

```bash
cd metricbeat
go test ./module/system/...
```

(cherry picked from commit eeabffa)

Co-authored-by: Orestis Floros <orestis.floros@elastic.co>

…s for zswap and cgroups v2 CPU CFS data (#49398)

* [Metricbeat] Bump elastic-agent-system-metrics for zswap and cgroups v2 CPU CFS data (#49098)

Bumps the elastic-agent-system-metrics dependency to [v0.14.3](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.3), [v0.14.2](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.2) also included.

### What's Changed
* Add Zswap Metrics by @orestisfl in elastic/elastic-agent-system-metrics#279
* PULL_REQUEST_TEMPLATE: Remove reference to non-existant CHANGELOG.md by @orestisfl in elastic/elastic-agent-system-metrics#286
* fix: remove shared context timeout from matrix tests by @orestisfl in elastic/elastic-agent-system-metrics#285
* Enable modernize linter and apply suggestions by @orestisfl in elastic/elastic-agent-system-metrics#287
* Use json omitzero for struct-typed fields in cgroup structs by @orestisfl in elastic/elastic-agent-system-metrics#288
* [cgv2] Add CPU CFS quota, period, and weight metrics by @orestisfl in elastic/elastic-agent-system-metrics#281
* Add missing zswap debug metrics by @orestisfl in elastic/elastic-agent-system-metrics#289

## Disruptive User Impact

None. New features.

## How to test this PR locally

1. Build metricbeat from the branch:

```bash
cd metricbeat
mage build
```

2. Create a test config file `metricbeat.test.yml`:

```yaml
metricbeat.modules:
  - module: system
    period: 5s
    metricsets:
      - memory
      - process
    process.include_top_n:
      by_cpu: 5
      by_memory: 5

output.console:
  pretty: true

logging.level: debug
```

3. Run metricbeat:

```bash
./metricbeat -e -c metricbeat.test.yml
```

4. Verify zswap memory metrics appear in the output (requires Linux with zswap enabled -- check with `cat /sys/module/zswap/parameters/enabled`):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "memory") | .system.memory.zswap'
```

Expected output (values will vary):

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976
}
```

5. To also verify the `zswap.debug.*` fields (requires debugfs access), grant the binary the `cap_dac_read_search` capability:

```bash
sudo setcap cap_dac_read_search=+ep metricbeat
```

Then re-run. Expected output with debug fields:

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976,
  "debug": {
    "decompress_fail": 0,
    "pool_limit_hit": 0,
    "pool_total_size": 950353920,
    "reject_alloc_fail": 0,
    "reject_compress_fail": 0,
    "reject_compress_poor": 0,
    "reject_kmemcache_fail": 0,
    "reject_reclaim_fail": 0,
    "stored_incompressible_pages": 16779,
    "stored_pages": 931031,
    "written_back_pages": 29111
  }
}
```

6. Verify `cfs.weight` appears in process cgroup metrics (requires cgroupsv2):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "process") | .system.process.cgroup.cpu.cfs.weight // empty'
```

7. Run unit tests:

```bash
cd metricbeat
go test ./module/system/...
```

(cherry picked from commit eeabffa)

# Conflicts:
#	metricbeat/module/system/fields.go

* Resolve cherry-pick conflict by regenerating fields.go

The auto-generated metricbeat/module/system/fields.go had merge
conflict markers from the backport cherry-pick. Regenerated using
`mage fields` based on the successfully merged _meta/fields.yml files.

---------

Co-authored-by: Orestis Floros <orestis.floros@elastic.co>

…v2 CPU CFS data (#49098)

Bumps the elastic-agent-system-metrics dependency to [v0.14.3](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.3), [v0.14.2](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.2) also included.

### What's Changed
* Add Zswap Metrics by @orestisfl in elastic/elastic-agent-system-metrics#279
* PULL_REQUEST_TEMPLATE: Remove reference to non-existant CHANGELOG.md by @orestisfl in elastic/elastic-agent-system-metrics#286
* fix: remove shared context timeout from matrix tests by @orestisfl in elastic/elastic-agent-system-metrics#285
* Enable modernize linter and apply suggestions by @orestisfl in elastic/elastic-agent-system-metrics#287
* Use json omitzero for struct-typed fields in cgroup structs by @orestisfl in elastic/elastic-agent-system-metrics#288
* [cgv2] Add CPU CFS quota, period, and weight metrics by @orestisfl in elastic/elastic-agent-system-metrics#281
* Add missing zswap debug metrics by @orestisfl in elastic/elastic-agent-system-metrics#289

## Disruptive User Impact

None. New features.

## How to test this PR locally

1. Build metricbeat from the branch:

```bash
cd metricbeat
mage build
```

2. Create a test config file `metricbeat.test.yml`:

```yaml
metricbeat.modules:
  - module: system
    period: 5s
    metricsets:
      - memory
      - process
    process.include_top_n:
      by_cpu: 5
      by_memory: 5

output.console:
  pretty: true

logging.level: debug
```

3. Run metricbeat:

```bash
./metricbeat -e -c metricbeat.test.yml
```

4. Verify zswap memory metrics appear in the output (requires Linux with zswap enabled -- check with `cat /sys/module/zswap/parameters/enabled`):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "memory") | .system.memory.zswap'
```

Expected output (values will vary):

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976
}
```

5. To also verify the `zswap.debug.*` fields (requires debugfs access), grant the binary the `cap_dac_read_search` capability:

```bash
sudo setcap cap_dac_read_search=+ep metricbeat
```

Then re-run. Expected output with debug fields:

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976,
  "debug": {
    "decompress_fail": 0,
    "pool_limit_hit": 0,
    "pool_total_size": 950353920,
    "reject_alloc_fail": 0,
    "reject_compress_fail": 0,
    "reject_compress_poor": 0,
    "reject_kmemcache_fail": 0,
    "reject_reclaim_fail": 0,
    "stored_incompressible_pages": 16779,
    "stored_pages": 931031,
    "written_back_pages": 29111
  }
}
```

6. Verify `cfs.weight` appears in process cgroup metrics (requires cgroupsv2):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "process") | .system.process.cgroup.cpu.cfs.weight // empty'
```

7. Run unit tests:

```bash
cd metricbeat
go test ./module/system/...
```

…v2 CPU CFS data (elastic#49098)

Bumps the elastic-agent-system-metrics dependency to [v0.14.3](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.3), [v0.14.2](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.2) also included.

### What's Changed
* Add Zswap Metrics by @orestisfl in elastic/elastic-agent-system-metrics#279
* PULL_REQUEST_TEMPLATE: Remove reference to non-existant CHANGELOG.md by @orestisfl in elastic/elastic-agent-system-metrics#286
* fix: remove shared context timeout from matrix tests by @orestisfl in elastic/elastic-agent-system-metrics#285
* Enable modernize linter and apply suggestions by @orestisfl in elastic/elastic-agent-system-metrics#287
* Use json omitzero for struct-typed fields in cgroup structs by @orestisfl in elastic/elastic-agent-system-metrics#288
* [cgv2] Add CPU CFS quota, period, and weight metrics by @orestisfl in elastic/elastic-agent-system-metrics#281
* Add missing zswap debug metrics by @orestisfl in elastic/elastic-agent-system-metrics#289

## Disruptive User Impact

None. New features.

## How to test this PR locally

1. Build metricbeat from the branch:

```bash
cd metricbeat
mage build
```

2. Create a test config file `metricbeat.test.yml`:

```yaml
metricbeat.modules:
  - module: system
    period: 5s
    metricsets:
      - memory
      - process
    process.include_top_n:
      by_cpu: 5
      by_memory: 5

output.console:
  pretty: true

logging.level: debug
```

3. Run metricbeat:

```bash
./metricbeat -e -c metricbeat.test.yml
```

4. Verify zswap memory metrics appear in the output (requires Linux with zswap enabled -- check with `cat /sys/module/zswap/parameters/enabled`):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "memory") | .system.memory.zswap'
```

Expected output (values will vary):

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976
}
```

5. To also verify the `zswap.debug.*` fields (requires debugfs access), grant the binary the `cap_dac_read_search` capability:

```bash
sudo setcap cap_dac_read_search=+ep metricbeat
```

Then re-run. Expected output with debug fields:

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976,
  "debug": {
    "decompress_fail": 0,
    "pool_limit_hit": 0,
    "pool_total_size": 950353920,
    "reject_alloc_fail": 0,
    "reject_compress_fail": 0,
    "reject_compress_poor": 0,
    "reject_kmemcache_fail": 0,
    "reject_reclaim_fail": 0,
    "stored_incompressible_pages": 16779,
    "stored_pages": 931031,
    "written_back_pages": 29111
  }
}
```

6. Verify `cfs.weight` appears in process cgroup metrics (requires cgroupsv2):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "process") | .system.process.cgroup.cpu.cfs.weight // empty'
```

7. Run unit tests:

```bash
cd metricbeat
go test ./module/system/...
```

…v2 CPU CFS data (elastic#49098)

Bumps the elastic-agent-system-metrics dependency to [v0.14.3](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.3), [v0.14.2](https://github.com/elastic/elastic-agent-system-metrics/releases/tag/v0.14.2) also included.

### What's Changed
* Add Zswap Metrics by @orestisfl in elastic/elastic-agent-system-metrics#279
* PULL_REQUEST_TEMPLATE: Remove reference to non-existant CHANGELOG.md by @orestisfl in elastic/elastic-agent-system-metrics#286
* fix: remove shared context timeout from matrix tests by @orestisfl in elastic/elastic-agent-system-metrics#285
* Enable modernize linter and apply suggestions by @orestisfl in elastic/elastic-agent-system-metrics#287
* Use json omitzero for struct-typed fields in cgroup structs by @orestisfl in elastic/elastic-agent-system-metrics#288
* [cgv2] Add CPU CFS quota, period, and weight metrics by @orestisfl in elastic/elastic-agent-system-metrics#281
* Add missing zswap debug metrics by @orestisfl in elastic/elastic-agent-system-metrics#289

## Disruptive User Impact

None. New features.

## How to test this PR locally

1. Build metricbeat from the branch:

```bash
cd metricbeat
mage build
```

2. Create a test config file `metricbeat.test.yml`:

```yaml
metricbeat.modules:
  - module: system
    period: 5s
    metricsets:
      - memory
      - process
    process.include_top_n:
      by_cpu: 5
      by_memory: 5

output.console:
  pretty: true

logging.level: debug
```

3. Run metricbeat:

```bash
./metricbeat -e -c metricbeat.test.yml
```

4. Verify zswap memory metrics appear in the output (requires Linux with zswap enabled -- check with `cat /sys/module/zswap/parameters/enabled`):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "memory") | .system.memory.zswap'
```

Expected output (values will vary):

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976
}
```

5. To also verify the `zswap.debug.*` fields (requires debugfs access), grant the binary the `cap_dac_read_search` capability:

```bash
sudo setcap cap_dac_read_search=+ep metricbeat
```

Then re-run. Expected output with debug fields:

```json
{
  "compressed": 950353920,
  "uncompressed": 3813502976,
  "debug": {
    "decompress_fail": 0,
    "pool_limit_hit": 0,
    "pool_total_size": 950353920,
    "reject_alloc_fail": 0,
    "reject_compress_fail": 0,
    "reject_compress_poor": 0,
    "reject_kmemcache_fail": 0,
    "reject_reclaim_fail": 0,
    "stored_incompressible_pages": 16779,
    "stored_pages": 931031,
    "written_back_pages": 29111
  }
}
```

6. Verify `cfs.weight` appears in process cgroup metrics (requires cgroupsv2):

```bash
./metricbeat -e -c metricbeat.test.yml 2>/dev/null | jq 'select(.metricset.name == "process") | .system.process.cgroup.cpu.cfs.weight // empty'
```

7. Run unit tests:

```bash
cd metricbeat
go test ./module/system/...
```