Phase 5: Alembic baseline, per-site deploy, ADRs to docs/adr

Migration runner ready and a sister site can deploy from a clean
checkout with one .env file.

ADRs relocated (migrations/adr/ -> docs/adr/):
- migrations/ is now Alembic territory, not docs.
- All cross-references updated: CLAUDE.md, docs/PLUGIN-HOOKS.md,
  docs/PLUGIN-QUICKSTART.md.

Alembic initialized (migrations/):
- env.py, script.py.mako, alembic.ini copied from Flask-Migrate
  templates so `flask db migrate` and `flask db upgrade` work without
  a one-time `flask db init` (which would clash with the existing
  migrations/ directory).
- Baseline migration generated via autogenerate, captures all 47
  tables (core models + 6 plugins) as the upgrade target. Ready for
  per-site `flask db upgrade` from an empty schema.

Deploy artifacts:
- Dockerfile: python:3.12-slim base, gunicorn server, non-root user,
  healthcheck against /api/auth/login. Single image bundles all six
  plugins; sites enable via `flask plugin install <name>`.
- docker-compose.yml: MySQL 8 + API container, healthcheck-gated
  startup, env-driven secrets that fail loud on missing values
  (`${SECRET_KEY:?}` form).
- .env.example: full env-var inventory with comments. Calls out
  required vs optional. Matches what ProductionConfig.validate
  enforces.

docs/DEPLOY.md:
- Step-by-step per-site runbook: clone, configure .env, bring up
  stack, run migrations, seed reference data, install plugins,
  create admin, front with TLS, backups, updates.
- Common-issues table.
- Cross-links to ADR-004 (per-site rationale), ADR-003 (plugin
  distribution), and the config source.

Skills:
- migrating-asset-schema: Alembic + one-shot data migration policy.
  Rules: additive first, renames are three steps, destructive ops
  need rollback, equipment migration filter per ADR-001 + ADR-005.
- hardening-flask-config: production validation, CORS allowlist
  policy, JWT cookie hardening, per-site deploy isolation per ADR-004.

CLAUDE.md updated to reflect the post-Phase-5 state. No tests added
this commit; the Alembic baseline is exercised by the existing
db.create_all-based test suite (tests do not touch the migration
runner; that's by design until per-plugin migrations land).

Test count unchanged: 101 passing.

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

docker-compose.yml

@@ -0,0 +1,58 @@
+# shopdb-flask single-site docker-compose template.
+#
+# Per ADR-004, each adopting facility runs its own stack. This template
+# brings up MySQL + the API container and exposes the API on port 5001.
+# The Vue frontend is served separately by the API in production builds
+# (see register_frontend_routes in shopdb/__init__.py); for dev, run
+# `npm run dev` in frontend/ on a separate port.
+#
+# Usage:
+#   cp .env.example .env
+#   # edit .env with site-specific secrets and origins
+#   docker compose up -d
+#
+# Refresh after pulling new code:
+#   docker compose build api
+#   docker compose up -d api
+
+services:
+  db:
+    image: mysql:8.0
+    restart: unless-stopped
+    environment:
+      MYSQL_ROOT_PASSWORD: ${MYSQL_ROOT_PASSWORD:?MYSQL_ROOT_PASSWORD must be set}
+      MYSQL_DATABASE: shopdb_flask
+      MYSQL_USER: shopdb
+      MYSQL_PASSWORD: ${MYSQL_PASSWORD:?MYSQL_PASSWORD must be set}
+    volumes:
+      - db_data:/var/lib/mysql
+    ports:
+      - "${MYSQL_PORT:-3306}:3306"
+    healthcheck:
+      test: ["CMD", "mysqladmin", "ping", "-h", "localhost", "-u", "root", "-p${MYSQL_ROOT_PASSWORD}"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
+  api:
+    build: .
+    restart: unless-stopped
+    depends_on:
+      db:
+        condition: service_healthy
+    environment:
+      FLASK_ENV: production
+      DATABASE_URL: mysql+pymysql://shopdb:${MYSQL_PASSWORD}@db:3306/shopdb_flask
+      SECRET_KEY: ${SECRET_KEY:?SECRET_KEY must be set}
+      JWT_SECRET_KEY: ${JWT_SECRET_KEY:?JWT_SECRET_KEY must be set}
+      CORS_ORIGINS: ${CORS_ORIGINS:?CORS_ORIGINS must be set}
+      LOG_LEVEL: ${LOG_LEVEL:-INFO}
+      ZABBIX_URL: ${ZABBIX_URL:-}
+      ZABBIX_TOKEN: ${ZABBIX_TOKEN:-}
+    ports:
+      - "${API_PORT:-5001}:5001"
+    volumes:
+      - ./plugins:/app/plugins:ro
+
+volumes:
+  db_data: