v0.24.0 — Pre-testing observability: debug logging, diagnostic dump, startup self-test

- Add [DEBUG] logging across all modules (backup, storage, sync, selfupdate,
  monitor, notify, report, assets, setup) gated behind logging.level: "debug"
- Add /api/debug/dump endpoint returning full controller state JSON (debug only)
- Add startup self-test validating 9 subsystems (Docker, dirs, storage, hub,
  restic repos, metrics DB) with pass/warn/fail summary
- New packages: internal/selftest, internal/util
- Constructor/signature changes: debug bool params, logger params on
  RunHealthCheck and BuildReport, smart watchdog probe logging

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

controller/README.md

@@ -4,7 +4,7 @@
 
 A single, lightweight Go container that replaces Portainer + scattered systemd scripts with a unified, Hungarian-language web dashboard for managing Docker Compose stacks, backups, storage, monitoring, and notifications on customer hardware.
 
-**Current version: v0.23.0**
+**Current version: v0.24.0**
 
 ---
 
@@ -100,7 +100,9 @@ A single, lightweight Go container that replaces Portainer + scattered systemd s
 | **Notify** | `internal/notify/` | Email notifications via hub relay, preference sync, per-event cooldowns |
 | **Report** | `internal/report/` | Hub report builder + HTTP pusher (system, stacks, backup, health) |
 | **Assets** | `internal/assets/` | Hub-managed asset syncer: downloads logos/screenshots with SHA-256 change detection |
-| **API** | `internal/api/` | REST JSON endpoints |
+| **SelfTest** | `internal/selftest/` | Startup self-test: 9 diagnostic checks (Docker, dirs, storage, hub, restic, metrics) |
+| **Util** | `internal/util/` | Shared utilities: `TruncateStr` for debug log output truncation |
+| **API** | `internal/api/` | REST JSON endpoints, diagnostic dump (`/api/debug/dump`) |
 | **Web** | `internal/web/` | Hungarian dashboard, auth, page handlers, template functions, alerts |
 
 ---
@@ -1265,6 +1267,12 @@ Config endpoints accept session auth OR `Authorization: Bearer <hub_api_key>` (s
 | POST | `/api/assets/sync` | Trigger on-demand asset sync from Hub (async) |
 | GET | `/api/assets/status` | Asset sync status (last sync, file count, total bytes) |
 
+### Debug (debug mode only)
+
+| Method | Endpoint | Description |
+|--------|----------|-------------|
+| GET | `/api/debug/dump` | Full diagnostic JSON dump (controller state, storage, stacks, backup, hub, scheduler, health, alerts). Returns 404 when `logging.level` is not `"debug"`. |
+
 Response format: `{"ok": true/false, "data": ..., "error": "...", "message": "..."}`
 
 ---
@@ -1355,6 +1363,9 @@ See `docker-compose.yml` for the full volume configuration.
 - [ ] Docker volume backup (`/var/lib/docker/volumes:ro`)
 - [ ] Raspberry Pi testing (pi-customer-1)
 - [x] CSRF protection on POST endpoints (v0.23.0)
+- [x] Verbose debug logging across all modules (v0.24.0)
+- [x] Diagnostic dump endpoint `/api/debug/dump` (v0.24.0)
+- [x] Startup self-test with 9 subsystem checks (v0.24.0)
 - [ ] Login rate limiting
 
 ---