docs: add production deployment example with volumes and .env

- docker/docker-compose.prod.yml: pulls image from 192.168.0.19:5000,
  mounts config/, wiki/ and db/ as separate volumes, health check, TZ support
- .env.example: fully commented template for all env vars
- .gitignore: ignore .env, always track .env.example
- README: deployment section with step-by-step guide, volume table, backup commands
- config.go: default db_path to /data/db/archivum.db (matches prod volume layout)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -115,6 +115,88 @@ npm run dev
 | `PUID` | `1000` | File system user ID |
 | `PGID` | `1000` | File system group ID |
 
+## Production Deployment
+
+### Directory layout on the host
+
+```
+/opt/archivum/
+├── config/
+│   └── config.json     ← written by Setup Wizard on first access
+├── wiki/               ← AsciiDoc files + git repository
+└── db/
+    └── archivum.db     ← SQLite database (auto-created)
+```
+
+### Steps
+
+```bash
+# 1. Create host directories
+mkdir -p /opt/archivum/{config,wiki,db}
+
+# 2. Set ownership to match PUID/PGID (default 1000:1000)
+chown -R 1000:1000 /opt/archivum
+
+# 3. Copy and edit the environment file
+cp .env.example .env
+# Edit .env — at minimum check PUID, PGID and HOST_PORT
+
+# 4. Allow the insecure local registry (if not already done)
+# Add to /etc/docker/daemon.json:
+#   { "insecure-registries": ["192.168.0.19:5000"] }
+# Then: sudo systemctl restart docker
+
+# 5. Pull and start
+docker compose -f docker/docker-compose.prod.yml pull
+docker compose -f docker/docker-compose.prod.yml up -d
+
+# 6. View logs
+docker compose -f docker/docker-compose.prod.yml logs -f
+```
+
+Open `http://<host>:8080` and complete the Setup Wizard.
+
+### Example `.env`
+
+```dotenv
+REGISTRY=192.168.0.19:5000
+IMAGE_TAG=latest
+
+ARCHIVUM_CONFIG=/opt/archivum/config
+ARCHIVUM_WIKI=/opt/archivum/wiki
+ARCHIVUM_DB=/opt/archivum/db
+
+HOST_PORT=8080
+PUID=1000
+PGID=1000
+TZ=Europe/Stockholm
+```
+
+> A fully commented template is available at [`.env.example`](.env.example).
+
+### Volumes at a glance
+
+| Container path | Maps to (default) | Purpose |
+|---|---|---|
+| `/config` | `/opt/archivum/config` | `config.json` (backend) + `settings.json` (frontend) |
+| `/data/wiki` | `/opt/archivum/wiki` | AsciiDoc source files + git repo |
+| `/data/db` | `/opt/archivum/db` | SQLite database (`archivum.db`) |
+
+### Backup
+
+```bash
+# Wiki content (git repo — just rsync or tar)
+tar czf archivum-wiki-$(date +%F).tar.gz /opt/archivum/wiki
+
+# Database
+cp /opt/archivum/db/archivum.db archivum-db-$(date +%F).db
+
+# Config
+cp /opt/archivum/config/config.json archivum-config-$(date +%F).json
+```
+
+---
+
 ## VS Code Tasks
 
 Open the Command Palette (`Ctrl+Shift+P`) → **Tasks: Run Task**: