feat(python): optimize FastAPI deployment with direct uvicorn entrypoint

[davideme]

Summary

• Direct uvicorn entrypoint: Replaces launcher.py in the Procfile with uvicorn main:app --host 0.0.0.0 --port 8080 --workers 4, following the Google Cloud Buildpacks recommended pattern for Python 3.13+; adds a main.py shim at the buildpack root to expose the app at the expected module path
• Fix lifespan shutdown bugs: settings.use_postgres was a method reference (always truthy, missing ()); db_manager was captured as None at import time so the engine pool was never closed — fixed by reading dependencies.db_manager through the module at shutdown
• Add httptools: C-level HTTP/1.1 parser replaces pure-Python h11; added to both pyproject.toml and requirements.txt since the buildpack uses requirements.txt for dependency installation
• Fix pre-commit hook: Pass --force-exclude to ruff so lint.exclude in pyproject.toml is honoured when files are passed explicitly (was inadvertently linting generated/excluded files)

Test plan

• Python CI passes (lint, unit tests, mode tests, schemathesis)
• Smoke test locally: uvicorn main:app --port 8080 starts and GET /health returns {"status":"ok","storage":"memory"}
• Cloud Build deployment uses Procfile entrypoint and starts with 4 workers

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR optimizes the FastAPI deployment for Google Cloud Buildpacks by replacing the Python launcher script with a direct uvicorn command in the Procfile, adding performance improvements via httptools, and fixing critical bugs in the application lifespan management.

Changes:

• Replaced launcher.py with direct uvicorn main:app command in Procfile and added a root-level main.py shim for buildpack compatibility
• Fixed two critical bugs in the lifespan shutdown: settings.use_postgres was missing () call, and db_manager was captured as None at import time
• Added httptools dependency for C-level HTTP parsing performance
• Fixed pre-commit hook to pass --force-exclude to ruff to honor exclusion configuration

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/python/src/openapi_server/main.py	Fixed lifespan shutdown bugs: corrected use_postgres() method call and changed to module-level dependencies.db_manager access
src/python/main.py	Added entrypoint shim to expose app at main:app path expected by buildpacks
src/python/Procfile	Replaced launcher.py with direct uvicorn command using hardcoded port 8080 and 4 workers
src/python/pyproject.toml	Added httptools dependency with >=0.5.0 constraint
src/python/requirements.txt	Added httptools 0.7.1 for buildpack installation
src/python/poetry.lock	Updated lock file with httptools 0.7.1 and updated content hash
scripts/hooks/python.sh	Added --force-exclude flag to ruff commands to honor pyproject.toml exclusions

[Copilot]

The hardcoded --port 8080 removes support for the PORT environment variable that was previously respected by launcher.py. Google Cloud Run and other platforms commonly use the PORT environment variable to dynamically assign ports. Consider using --port $PORT or ${PORT:-8080} to maintain backward compatibility while providing a sensible default. Uvicorn also respects the PORT environment variable automatically if --port is not specified, so you could remove the explicit port flag entirely.

Suggested change

	web: uvicorn main:app --host 0.0.0.0 --port 8080 --workers 4
	web: uvicorn main:app --host 0.0.0.0 --workers 4

[Copilot]

The version constraint >=0.5.0 is inconsistent with the locked version 0.7.1 in poetry.lock. Poetry's caret (^) constraints are more conventional for non-zero major versions and better express semantic versioning expectations. Consider using ^0.7.0 or ^0.5.0 instead of >=0.5.0 to prevent accidentally pulling in breaking changes from hypothetical future major versions while still allowing minor and patch updates.

Suggested change

	httptools = ">=0.5.0"
	httptools = "^0.7.0"

[Copilot]

The hardcoded --workers 4 removes support for the WORKERS environment variable that was previously respected by launcher.py. Different deployment environments may need different worker counts based on available resources. Consider using --workers ${WORKERS:-4} to maintain backward compatibility while providing a sensible default, or allow the platform to configure this through environment variables at deployment time.

Suggested change

	web: uvicorn main:app --host 0.0.0.0 --port 8080 --workers 4
	web: uvicorn main:app --host 0.0.0.0 --port 8080 --workers ${WORKERS:-4}

[Copilot]

The new Procfile hardcodes port 8080 and 4 workers, but the README.md still documents that PORT and WORKERS environment variables are supported via the launcher script (lines 172-173). Since the Procfile now uses direct uvicorn invocation instead of launcher.py, the documentation needs to be updated to reflect the current behavior. Either update the README to document the new hardcoded values, or modify the Procfile to continue supporting these environment variables.