Phase 0 milestone 0.1: repo scaffold + Docker Compose

Scaffolding for the YPMS in-house build. Mirrors OWC's structure so
future OWC framework code can be vendored in with minimal fiddling
(milestone 0.2).

Includes:

- pyproject.toml — Python 3.12, FastAPI, SQLAlchemy 2.x, Alembic,
  Postgres, pydantic-settings, structlog, cryptography. Dev extras:
  pytest, ruff, mypy, bandit, pip-audit.
- Dockerfile — multi-stage builder + slim runtime.
- docker-compose.yml — app + Postgres (on 5433 to avoid clashing with
  OWC on 5432) + Adminer (on 8081).
- alembic.ini + migrations/env.py + baseline 0001_baseline.py (empty
  by design; every future change is additive and immutable once merged).
- src/ypms/main.py — FastAPI factory with /healthz and /readyz.
- src/ypms/settings.py — pydantic-settings config (DB URL, JWT,
  column encryption key, log level, env, CORS).
- src/ypms/logging.py — structlog + sanitize_for_log() for the
  sensitive-fields-never-in-logs rule from ARCHITECTURE.md §10.1.
- src/ypms/db.py — SQLAlchemy Base, engine, session factory, get_db.
- src/ypms/middleware.py — RequestIdMiddleware; X-Request-ID header
  echoed both ways.
- src/ypms/framework/ and src/ypms/security/ — empty packages, to be
  populated in milestones 0.2 and 0.3-0.4.
- tests/test_health.py — 3 smoke tests (healthz OK, header present,
  header honoured on incoming).
- README.md — quickstart.
- CONTRIBUTING.md — hard rules mirrored from OWC.
- .github/workflows/ci.yml — lint (ruff), types (mypy), tests + 80%
  coverage floor, SAST (bandit), SCA (pip-audit), gitleaks.

Green locally: ruff clean, mypy clean, pytest 3 passed.

Advances YPMS-POAM-040 (architecture doc + Phase 0 kickoff).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

migrations/script.py.mako

@@ -0,0 +1,27 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from __future__ import annotations
+
+from collections.abc import Sequence
+
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+revision: str = ${repr(up_revision)}
+down_revision: str | Sequence[str] | None = ${repr(down_revision)}
+branch_labels: str | Sequence[str] | None = ${repr(branch_labels)}
+depends_on: str | Sequence[str] | None = ${repr(depends_on)}
+
+
+def upgrade() -> None:
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    ${downgrades if downgrades else "pass"}