…in#40)

Implement comprehensive chaos testing for Kafka broker failures to validate
system resilience and recovery capabilities.

## Changes

### New Test Implementation
- **test/chaos/scenario_02_kafka_broker_failure_test.go**: Complete chaos test
  for Kafka broker failure scenarios with 9 test phases:
  1. Baseline performance validation
  2. Latency injection (3s via toxiproxy)
  3. Sync producer behavior under latency
  4. Async producer behavior under latency
  5. Complete broker failure simulation (100% connection drops)
  6. Producer failure handling validation
  7. Consumer failure handling validation
  8. System recovery verification
  9. Message consistency validation

### Test Automation
- **test/chaos/run_scenario_02.sh**: Automated test runner with:
  - Pre-flight checks for Kafka and toxiproxy services
  - Auto-start docker compose if needed
  - Service connectivity verification
  - Automatic cleanup after test completion
  - Colored output for better readability

### Infrastructure Fixes
- **compose/docker-compose-ss.yml**:
  - Pin PostgreSQL to version 16 (prevent breaking upgrades)
  - Expose Kafka ports 9092 and 9093 to host
  - Update Kafka advertise listener to localhost for external access
  - Fixes PostgreSQL restart loop and Kafka connectivity issues

### Documentation
- **test/chaos/README.md**: Updated with:
  - Complete Scenario 2 documentation
  - Test phases and expected results
  - Usage instructions with helper scripts
  - Updated test duration estimates
  - Marked Scenario 2 as implemented

## Test Results

All tests passing (132.26 seconds):
- ✅ Baseline Performance
- ✅ Latency Injection
- ✅ Producer With Latency (sync and async)
- ✅ Broker Failure Injection
- ✅ Producer/Consumer Under Failure
- ✅ Recovery Verification
- ✅ Message Consistency

## Testing

```bash
# Run Scenario 2 only
./test/chaos/run_scenario_02.sh

# Run all chaos tests
go test -v ./test/chaos/...
```

## Prerequisites

- Docker compose with toxiproxy-kafka running
- Kafka accessible on localhost:9092 (direct) and localhost:19092 (via toxiproxy)
- Toxiproxy API on localhost:8475

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Co-authored-by: oskarszoon <1449115+oskarszoon@users.noreply.github.com>

…he (#842)

Pins github.com/bitcoin-sv/bdk/module/gobdk to a pseudo-version of the
hot-fix on top of v1.2.3 (bitcoin-sv/bdk PR #40) that adds a per-instance
CachingScriptChecker overriding CheckSig to short-circuit identical
signature verifications within one EvalScript run.

Without the hot-fix the validator stalls for hours on testnet block
1,451,505 / tx 7bc9a3408dd0c87b835c887a0bce22c20788fc3c4b953929d4367656d80acab5,
whose 490 KB locking script performs 245,001 identical ECDSA verifications.
The cgo entry point is uninterruptible from Go so it presents to operators
as a hang in _Cfunc_ScriptEngine_VerifyScript. With the hot-fix the
verifier completes in ~70 s.

Do not bump gobdk to v1.2.4 (or later) until bitcoin-sv/bdk PR #41 — the
master/v1.2.4 port of the same hot-fix — has been merged.