controller v0.69.0: remove dead infra-backup stubs + unused restic-password report field

Controller half of Phase-1 Infra Backup retirement (hub v0.12.0;
SPIKE-infra-backup-2026-06-15). Pure dead-code removal, no behaviour change.

- Remove Pusher.PushInfraBackup (caller-less; hub endpoint gone).
- Remove Notifier.NotifyBackupCompleted / backup_completed event (caller-less
  since slice 8C; hub deadline check now reads agent host-report PBS snapshots).
- Remove report.BackupReport.ResticPassword — builder never sets it post-8C
  (confirmed in source + live), but it historically leaked the restic password
  into the hub's plaintext reports store.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -1,5 +1,22 @@
 ## Changelog
 
+### v0.69.0 — remove dead infra-backup stubs + the unused restic-password report field (2026-06-16)
+
+Controller half of the Phase-1 Infra Backup retirement (hub v0.12.0; see
+`felhom.eu/documentation/audits/SPIKE-infra-backup-2026-06-15.md`). Pure dead-code removal — no
+behaviour change (everything removed was already caller-less).
+
+- **Removed `report.Pusher.PushInfraBackup`** — pushed the infra-backup payload to the now-removed hub
+  endpoint `POST /api/v1/infra-backup`. Dead since slice 8C; no callers.
+- **Removed `notify.Notifier.NotifyBackupCompleted`** (the `backup_completed` event) — no callers
+  since whole-guest backup moved to the agent in slice 8C. The hub's backup-deadline check now reads
+  the agent host-report's PBS snapshots instead of this event. `NotifyBackupFailed` and the DB-dump
+  notifiers are untouched and still used.
+- **Removed `report.BackupReport.ResticPassword`** (`json:"restic_password"`) — the live report
+  builder (`buildBackupReport`) has left it empty since slice 8C, but the field historically leaked
+  the restic password into the hub's plaintext `reports` store. Confirmed via pushed source (builder
+  never sets it) **and** live data (current reports carry no `restic_password`) before removal.
+
 ### v0.68.3 — fix Beállítások page endless-refresh loop after a migration (2026-06-15)
 
 Found while live-validating the M3 migration: once any data migration finished, the **Beállítások