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/specs/docker-deployment/spec.md

@@ -32,27 +32,31 @@ The project SHALL include docker-compose.yml for simplified deployment orchestra
 
 #### Scenario: Service definition
 - **WHEN** docker-compose.yml is parsed
-- **THEN** defines single service named 'candle-annotator' using Dockerfile from current directory
+- **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 (configurable via PORT environment variable)
+- **THEN** maps host port 3000 to container port 3000
 
-#### Scenario: Volume mounting for database
+#### Scenario: Volume mounting for ML data
 - **WHEN** docker-compose up runs
-- **THEN** mounts named volume 'candle-data' to /app/data in container for SQLite database persistence
+- **THEN** mounts named volume 'ml-data' to /app/ml-data in the candle-annotator container
 
-#### Scenario: Environment variable configuration
-- **WHEN** docker-compose.yml is used
-- **THEN** supports loading environment variables from .env file for NODE_ENV, PORT, and other configs
+#### 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: Volume declaration
+#### Scenario: No SQLite volume
 - **WHEN** docker-compose.yml is parsed
-- **THEN** declares 'candle-data' as named volume in volumes section
+- **THEN** there is no `candle-data` volume defined or mounted
 
 ### Requirement: Environment variable configuration
 The project SHALL use environment variables for runtime configuration.
@@ -61,6 +65,14 @@ The project SHALL use environment variables for runtime configuration.
 - **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)
@@ -69,14 +81,6 @@ The project SHALL use environment variables for runtime configuration.
 - **WHEN** NODE_ENV environment variable is set to 'production'
 - **THEN** Next.js runs in production mode with optimizations enabled
 
-#### Scenario: Database path configuration
-- **WHEN** DATABASE_PATH environment variable is set (optional)
-- **THEN** SQLite database file is created at specified path (default: ./data/candles.db)
-
-#### Scenario: HOSTNAME configuration
-- **WHEN** HOSTNAME environment variable is set
-- **THEN** Next.js server binds to specified hostname (default: 0.0.0.0 for containers)
-
 ### Requirement: Health check endpoint
 The API SHALL provide a health check endpoint for container orchestration.
 
@@ -86,7 +90,7 @@ The API SHALL provide a health check endpoint for container orchestration.
 
 #### Scenario: Database connection check
 - **WHEN** GET request sent to `/api/health?check=db`
-- **THEN** system attempts simple database query and returns 200 if successful, 503 if database unavailable
+- **THEN** system attempts a PostgreSQL query and returns 200 if successful, 503 if database unavailable
 
 #### Scenario: Health check in Dockerfile
 - **WHEN** Dockerfile defines HEALTHCHECK
@@ -138,23 +142,19 @@ The Docker image SHALL be optimized for production use with minimal size.
 - **THEN** final image size is under 200MB (excluding data volume)
 
 ### Requirement: Database persistence
-The deployment SHALL ensure SQLite database persists across container restarts.
+The deployment SHALL ensure PostgreSQL data persists across container restarts.
 
-#### Scenario: Volume mounting
-- **WHEN** container runs with volume mount
-- **THEN** /app/data directory is mounted from host or Docker volume
-
-#### Scenario: Database file location
-- **WHEN** application initializes database
-- **THEN** SQLite file is created at /app/data/candles.db (inside mounted volume)
+#### 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** container is stopped and restarted
-- **THEN** existing database file is reused and all annotations and candles remain intact
+- **WHEN** the postgres container is stopped and restarted
+- **THEN** all database tables and data remain intact
 
-#### Scenario: File permissions
-- **WHEN** container creates database file
-- **THEN** appuser has read/write permissions to /app/data directory
+#### Scenario: PostgreSQL database name
+- **WHEN** the postgres service starts
+- **THEN** the `POSTGRES_DB` environment variable is set to `candle_annotator`
 
 ### Requirement: Deployment documentation
 DEPLOYMENT.md SHALL include comprehensive Docker deployment instructions.