fix: production uses :latest image, not :dev
docs: comprehensive Development Guide update
- Add complete data source integration pattern (server.js insertion points, metric guarding, prepared statements)
- Add Settings UI patterns (pre-save testing, global metric exclusion, unsaved changes)
- Add profile-based source architecture (Modbus/RS232/Dongle metric mapping conversion)
- Add Backup & Restore architecture with WAL checkpointing requirement
- Add Performance best practices (prepared statements, compression, cache headers, query consolidation)
- Add Deployment section (Docker workflow, stale code detection, zombie process fix)
- Add Common Pitfalls section (11 documented traps with fixes)
- Add Git Conventions and server port configuration
- Fix Node.js version requirement (v22 via /usr/bin/node, not generic 18+)
- Complete module list (add rs232, dongle, pvoutput)
Updated Development Guide (markdown)
Updated Developer Guide (markdown)