v0.55.0: raw-device discovery + registry-sourced drive tracking (Impl-2a)

GET /disks/candidates enumerates host disks the Impl-1 unclaimed filter proves
free (init/attach split). RegistryKnownTargets sources the watchdog's known-drive
set from the intent registry + Felhom .mount units (not Observe/PVE storages) —
decouples drive health from PVE storage (closes the registry-only false-detach
class); Observe kept for real PVE storages + a deduped /disks union. Idempotent
existing-drive migration at start. Tests + red-proof (Observe misses a
registry-only drive; registry provider tracks it). go build/vet/test clean.

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

CHANGELOG.md

@@ -1,3 +1,31 @@
+## v0.55.0 — raw-device discovery + registry-sourced drive tracking (Impl-2a) (2026-07-01)
+
+Agent backend for drive enrollment (SPIKE-drive-enrollment §SQ1/SQ4/SQ5). Makes raw (non-PVE-storage)
+drives (a) discoverable for enrollment and (b) health-tracked WITHOUT being a PVE storage — so a drive
+enrolled the new way isn't enrolled-but-untracked (the 3b-fix false-detach class). No mkfs here (Impl-1
+owns it); the controller wizard rewiring is Impl-2b.
+
+- **`GET /disks/candidates`** (`internal/storage/candidates.go` + `internal/localapi/disks.go`):
+  enumerates host whole-disks from `/sys/block`, runs the Impl-1 unclaimed filter, and returns the free
+  ones with probe info (size/model/FS/data-bearing/durable-id preview), split into `initialize` (all
+  unclaimed) and `attach` (the subset carrying a mountable ext4/xfs FS). Fail-safe carries through (a
+  device not provably unclaimed is omitted).
+- **`RegistryKnownTargets`** (`internal/storage/registry_known.go`): the watchdog's known-DRIVE set now
+  comes from the intent registry + Felhom `.mount` units, NOT `Observe()` (PVE storages). A unit is
+  tracked iff its intent ≠ `new` (enrolled/ejected/decommissioned; the watchdog's existing IntentReader
+  gate still decides re-mount). `main.go` swaps the watchdog `KnownTargets` source. **`Observe()` is
+  KEPT** for real PVE storages (local/local-lvm/pbs) — reports + the `/disks` view.
+- **`handleDisks` union:** additive + deduped-by-mount-path — appends registry drives Observe doesn't
+  surface (a registry-only drive now appears in the agent-view) without dropping any Observe row (can't
+  regress the current view).
+- **Existing-drive migration** (`ReconcileExistingDrives`, idempotent, at agent start): records each
+  currently-mounted Felhom-unit drive as `enrolled` so the registry-sourced `Known()` tracks it without
+  its legacy PVE dir-storage. Does NOT create/remove PVE storages.
+- **Tests:** RegistryKnownTargets (enrolled tracked / new excluded / ejected tracked) + the **red-proof**
+  (Observe-based `Known()` misses a drive with no PVE storage; the registry provider tracks it);
+  migration idempotency; candidates init/attach split. `go build`/`vet`/`test ./...` clean. Watchdog/
+  HostLiveness/Remounter unchanged (only the source injected).
+
 ## v0.54.0 — format-safety foundation: unclaimed-disk guard + guarded-mkfs wrapper (2026-07-01)
 
 Impl-1 (SPIKE-drive-enrollment-2026-07-01). Hardens the destructive `Format`/mkfs path BEFORE the