Introduces `pacquet-reporter` carrying the typed `LogEvent` enum, the
no-`self` `Reporter` capability trait per #339, and `NdjsonReporter` /
`SilentReporter` implementations. Adds the `--reporter=ndjson|silent`
flag and threads a `R: Reporter` generic through `Install::run`,
emitting `pnpm:stage` `importing_started` / `importing_done` to
bracket the install — one channel wired end-to-end as a smoke test
for the schema-mirror approach.

The wire format mirrors what `@pnpm/core-loggers` defines and
`@pnpm/cli.default-reporter` consumes under `pnpm --reporter=ndjson`.

Engine only. The JS-reporter spawn-and-pipe (`--reporter=default`),
the backfill of missing log events in already-ported code (#347), and
the porting convention in AGENTS.md (#346) land in follow-up PRs. The
default reporter is `silent` until the spawn-and-pipe exists, so user-
facing output is unchanged.

Refs #345. Design: #344.

…ceDir

Upstream emits stage events with `prefix: lockfileDir` — the directory
holding `pnpm-lock.yaml`, which collapses to the workspace root when a
workspace is present. The previous comment described the *result* in
pacquet's no-workspace world but didn't name the upstream concept or
point at the helper to mirror once workspaces land. Replacing the
comment with a TODO that links `findWorkspaceDir` makes the migration
path explicit so the next person editing this site doesn't have to
re-derive it.

No behavior change.

Address feedback on the reporter PR.

reporter:
- Drop the dependency-injection issue link (#339) from `Reporter`,
  the recording-fake test, and the module-level docs; convention is
  visible from the code.
- Wrap `bunyan` and `bole` references as markdown links.
- Demote `Envelope`'s `#[serde(flatten)]` rationale to a regular `//`
  comment so private impl detail isn't part of `///` rustdoc.
- Introduce `pub trait EnvVar` + `pub struct RealEnvVar` (reporter-
  local capability trait) and split `hostname` into a generic
  `resolve_hostname<E>` plus a non-generic cached production wrapper.
  Add four unit tests covering `HOSTNAME`, `COMPUTERNAME` fallback,
  precedence, and the unset case.
- Switch the wire-shape test to `pipe-trait`; add `pipe-trait` to
  dev-dependencies.
- Fix intra-link rule violation in the `SilentReporter` test doc.

package-manager:
- Tighten the install `prefix` extraction to fail loudly on
  non-UTF-8 / parentless manifest paths instead of silently emitting
  an empty string. Workspace-aware resolution tracked at #357.
- Replace `concat!` YAML literals in two tests with
  `text_block_macros::text_block!`; add as dev-dependency.
- Convert bare-prose identifiers in
  `install_emits_stage_events_bracketing_the_run` to intra-doc
  links; drop the recording-fake DI prose.

Long inline `mod tests` extraction tracked at #358.

…ility

Address the second round of review feedback on #349.

reporter:
- Replace env-var-based hostname (HOSTNAME / COMPUTERNAME) with the
  real gethostname(2) syscall via the `gethostname` crate. The
  env-var approach was unsound: shells set `HOST` (zsh) or
  `HOSTNAME` (bash) as private variables that don't propagate to
  spawned binaries, so a packaged `pacquet` would have observed an
  empty hostname in most production environments.
- Introduce `pub trait GetHostName` + `pub struct RealApi`. Real
  resolution lives in `RealApi::get_host_name`. Tests can supply
  their own impl.
- Cache the production value in `static HOSTNAME: LazyLock<String>
  = LazyLock::new(RealApi::get_host_name)`. The wire emit path
  reads `&HOSTNAME` directly; the previous `hostname()` wrapper is
  no longer needed.
- Drop the now-redundant `EnvVar` trait, `RealEnvVar`,
  `resolve_hostname`, and the four env-resolution unit tests (those
  scenarios no longer exist after the syscall switch).

reporter test layout:
- Move the tests module into its own file at
  `crates/reporter/src/tests.rs` per the unit-test-layout rule in
  `CODE_STYLE_GUIDE.md`. Drop `use super::*` in favor of explicit
  merged imports of just the items the tests touch.
- Two new tests: `get_host_name_capability_is_mockable` (proves the
  trait dispatch works for fakes) and
  `real_api_returns_a_non_empty_host_name` (smoke-checks the real
  syscall path).

Documentation style:
- Restructure the workspace-prefix and stage-bracketing comments to
  drop em dashes per `CONTRIBUTING.md`'s writing-style guidance and
  to render `bunyan` as a markdown link.
- Fix the `@pnpm/core-loggers` link to point at the package
  directory rather than its `src` subdirectory.

Imports:
- Replace seven occurrences of `pacquet_reporter::SilentReporter`
  qualified at the call site with a single `use pacquet_reporter::
  SilentReporter` in the test module.