chore: archive ml-db-consolidation change and sync specs

- Archived change to openspec/changes/archive/2026-02-17-ml-db-consolidation/
- Created new postgres-data-layer spec with PostgreSQL connection, schema definitions, Drizzle migrations, npm deps, and SQLite migration requirements
- Updated docker-deployment spec: Docker Compose now PostgreSQL-based (postgres dependency, ml-data volume, DATABASE_URL); env vars updated (DATABASE_URL added, DATABASE_PATH removed); database persistence updated to PostgreSQL volumes; health check updated to PostgreSQL
- Updated ml-training spec: added database name scenario (candle_annotator) and new direct annotation data access requirement

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

openspec/changes/archive/2026-02-17-ml-db-consolidation/specs/docker-deployment/spec.md

@@ -0,0 +1,81 @@
+## MODIFIED Requirements
+
+### Requirement: Docker Compose configuration
+The project SHALL include docker-compose.yml for simplified deployment orchestration.
+
+#### Scenario: Service definition
+- **WHEN** docker-compose.yml is parsed
+- **THEN** defines service named 'candle-annotator' using Dockerfile from current directory
+
+#### Scenario: Port mapping
+- **WHEN** docker-compose up runs
+- **THEN** maps host port 3000 to container port 3000
+
+#### Scenario: Volume mounting for ML data
+- **WHEN** docker-compose up runs
+- **THEN** mounts named volume 'ml-data' to /app/ml-data in the candle-annotator container
+
+#### Scenario: Frontend depends on PostgreSQL
+- **WHEN** docker-compose up runs
+- **THEN** the candle-annotator service starts only after the postgres service is healthy (`depends_on: postgres: condition: service_healthy`)
+
+#### Scenario: Frontend DATABASE_URL
+- **WHEN** the candle-annotator service starts
+- **THEN** the `DATABASE_URL` environment variable is set to `postgresql://ml_user:ml_password@postgres:5432/candle_annotator`
+
+#### Scenario: Restart policy
+- **WHEN** container crashes or stops
+- **THEN** docker-compose automatically restarts container unless explicitly stopped (restart: unless-stopped)
+
+#### Scenario: No SQLite volume
+- **WHEN** docker-compose.yml is parsed
+- **THEN** there is no `candle-data` volume defined or mounted
+
+### Requirement: Environment variable configuration
+The project SHALL use environment variables for runtime configuration.
+
+#### Scenario: .env.example file
+- **WHEN** repository is cloned
+- **THEN** includes .env.example file documenting all configurable environment variables with example values
+
+#### Scenario: DATABASE_URL configuration
+- **WHEN** `DATABASE_URL` environment variable is set
+- **THEN** the Next.js application connects to the PostgreSQL database at the specified URL
+
+#### Scenario: No DATABASE_PATH variable
+- **WHEN** environment variables are inspected
+- **THEN** there is no `DATABASE_PATH` variable (SQLite path is removed)
+
+#### Scenario: PORT configuration
+- **WHEN** PORT environment variable is set
+- **THEN** Next.js server listens on specified port (default: 3000)
+
+#### Scenario: NODE_ENV configuration
+- **WHEN** NODE_ENV environment variable is set to 'production'
+- **THEN** Next.js runs in production mode with optimizations enabled
+
+### Requirement: Database persistence
+The deployment SHALL ensure PostgreSQL data persists across container restarts.
+
+#### Scenario: PostgreSQL volume
+- **WHEN** docker-compose up runs
+- **THEN** the `postgres-data` named volume is mounted to `/var/lib/postgresql/data` in the postgres container
+
+#### Scenario: Container restart preserves data
+- **WHEN** the postgres container is stopped and restarted
+- **THEN** all database tables and data remain intact
+
+#### Scenario: PostgreSQL database name
+- **WHEN** the postgres service starts
+- **THEN** the `POSTGRES_DB` environment variable is set to `candle_annotator`
+
+### Requirement: Health check endpoint
+The API SHALL provide a health check endpoint for container orchestration.
+
+#### Scenario: Health check endpoint responds
+- **WHEN** GET request sent to `/api/health`
+- **THEN** system returns 200 status with JSON `{ status: 'ok', timestamp: <unix_timestamp> }`
+
+#### Scenario: Database connection check
+- **WHEN** GET request sent to `/api/health?check=db`
+- **THEN** system attempts a PostgreSQL query and returns 200 if successful, 503 if database unavailable