feat(chassis): SDK-native chassis behind L9_CHASSIS + W4-04 audit pool wiring

[cryptoxdog]

Why one PR

These two bodies of work share engine/handlers.py and engine/boot.py. The SDK chassis wraps the same GraphLifecycle that W4-04 modifies, and both depend on the new ACTION_HANDLERS registry. Splitting them would mean shipping a broken intermediate state or resolving the same conflict twice.

1. SDK-native chassis — dormant by default

L9_CHASSIS=legacy (the default) preserves today's behavior exactly. L9_CHASSIS=sdk selects the new path.

File	Role
chassis/entrypoint.py	Single uvicorn target dispatching on L9_CHASSIS
chassis/node_app.py	Builds the app via constellation-node-sdk create_node_app
chassis/handler_registration.py	Registers ACTION_HANDLERS with the SDK registry + packet audit wrapper

SdkLifecycleAdapter bridges engine.boot.GraphLifecycle (which subclasses the legacy LifecycleHook) onto the SDK's unrelated LifecycleHook ABC. Keeping the adapter in chassis/ means engine/boot.py stays free of SDK imports while both chassis run in parallel.

Every launch site now points at chassis.entrypoint:create_app — Makefile, Dockerfile.prod, scripts/entrypoint.sh, docker-compose.yml — so switching chassis is a config change, not a command change.

Single action registry

engine/handlers.py now exports ACTION_HANDLERS. chassis/actions.py consumes it instead of maintaining its own dict, so the legacy and SDK chassis cannot expose different action sets. tests/contracts/test_chassis_parity.py fails if a future edit reintroduces a hand-maintained list in either one.

2. W4-04 Postgres audit pool

The ComplianceEngine consumer side is already on main; only the wiring was missing.

GraphLifecycle.startup() creates an asyncpg pool when POSTGRES_DSN is set and passes it through init_dependencies() to EngineState.db_pool. shutdown() closes it.

This is a soft dependency: an unset or unreachable DSN leaves db_pool as None and logs a warning rather than blocking startup — the same graceful-degrade pattern as the existing Neo4j connection. EngineState.health_check() reports db_pool_present.

docker-compose.yml gains a postgres:16-alpine service seeded from engine/packet/packet_store.sql.

3. Chassis consolidation

Deletes chassis/app.py (371 lines) and chassis/auth/app.py (208 lines), which duplicated chassis/chassis_app.py. All imports and launch sites repointed. This clears the chassis/auth/app.py item in memory-bank/tech-debt.md.

4. Hermetic settings under pytest

engine/config/settings.py sets env_file=None when pytest is in sys.modules, so a developer's local .env cannot leak opt-in feature flags into the test suite.

Verification

1667 passed, 15 skipped, 56 xfailed
ruff check    — All checks passed
ruff format   — 18 files already formatted
contract scan — no violations

mypy engine/ reports one error (engine/inference_rule_registry.py:462 syntax) that reproduces on clean origin/main — pre-existing, not introduced here.

Deliberately out of scope

• L9_META headers are left at main's schema v1 so this does not collide with the schema v2 stamp in feat(meta): config-driven L9_META pipeline, schema v2, full-repo stamp #147.
• Docs still referencing chassis/app.py (docs/contracts/api/openapi.yaml, DEPENDENCY_INJECTION.md, config/env-contract.yaml) are owned by docs(contracts): align the YAML registry and the prose docs into one registry #146 — left untouched to avoid conflicts.
• tools/l9_meta_injector.py still lists the two deleted files in its registry; feat(meta): config-driven L9_META pipeline, schema v2, full-repo stamp #147 replaces that module wholesale.
• VPS deploy targets and the Docker git install from fix/docker-git-deps-and-proprietary-license are not included.

Made with Cursor

[github-actions]

❌ PR Too Large
Reviewable lines changed: 1839
Limit: 1000 lines
Action Required: Break into smaller, atomic PRs

📋 Best Practices for Large Changes

1. Refactoring + Features: Separate into 2 PRs
2. Multiple Features: One PR per feature
3. Database + Code: Separate migration from logic
4. Generated Code: Exclude it from reviewable-size accounting

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🚫 This PR is blocked until reviewable size limits are met.

[sonarqubecloud]

Quality Gate failed

Failed conditions
E Security Rating on New Code (required ≥ A)

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