Make container more robust (#95)

Reviewed-on: #95

12 files changed (+149, -66)
Key changes:
1. Monolithic container — Replaced the two-service compose setup (backend + frontend/caddy) with a single timetracker container. Caddy is now built into the image rather than running as a separate container.
2. Supervisord process manager — Added supervisor.conf and installed supervisor in the Dockerfile. entrypoint.sh now delegates to supervisord to manage three processes: Caddy, Gunicorn, and Qcluster — replacing manual trap/signaling logic.
3. Bundled Caddy — The Dockerfile now downloads and installs Caddy v2.9.1 directly into the image (/usr/local/bin/caddy). The Caddyfile was updated to use reverse_proxy localhost:8001 and serves static files from /home/timetracker/app/static.
4. Configurable deployment — Added .env.example with configurable environment variables: TZ, PUID/PGID, TIMETRACKER_EXTERNAL_PORT, DATA_DIR, CSRF_TRUSTED_ORIGINS. docker-compose.yml now references these with sensible defaults.
5. UID/GID flexibility — entrypoint.sh uses usermod/groupmod at startup to remap the timetracker user to the host-specified PUID/PGID, avoiding permission issues with mounted volumes.
6. Database & static files — settings.py now respects DATA_DIR env var for the SQLite database path. STATIC_ROOT changed to BASE_DIR / "static".
7. Dev improvements — New Caddyfile.dev (with browse enabled for static files) and updated Makefile dev-prod target runs Caddy alongside Django in development.
8. Tests — Re-enabled the test step in the Docker build GitHub Actions workflow.

timetracker/settings.py

@@ -4,7 +4,7 @@ Django settings for timetracker project.
 Generated by 'django-admin startproject' using Django 4.1.4.
 
 For more information on this file, see
-https://docs.djangoproject.com/en/4.1/topics/settings/
+https://docs.djangoproject.com/en/4.1/topics/deployment/checklist/
 
 For the full list of settings and their values, see
 https://docs.djangoproject.com/en/4.1/ref/settings/
@@ -110,7 +110,7 @@ WSGI_APPLICATION = "timetracker.wsgi.application"
 DATABASES = {
     "default": {
         "ENGINE": "django.db.backends.sqlite3",
-        "NAME": BASE_DIR / "db.sqlite3",
+        "NAME": Path(os.environ.get("DATA_DIR", str(BASE_DIR))) / "db.sqlite3",
         "OPTIONS": {
             "timeout": 20,
             "init_command": "PRAGMA synchronous=FULL; PRAGMA journal_mode=WAL;",
@@ -154,7 +154,7 @@ USE_TZ = True
 # https://docs.djangoproject.com/en/4.1/howto/static-files/
 
 STATIC_URL = "static/"
-STATIC_ROOT = BASE_DIR / "static" if DEBUG else "/var/www/django/static"
+STATIC_ROOT = BASE_DIR / "static"
 
 # Default primary key field type
 # https://docs.djangoproject.com/en/4.1/ref/settings/#default-auto-field