v0.39.0 — DR-recipe completion: live PBS coord + drop role/restic_repo_coord from v1 drive shape

Live PBS coord: new internal/pbs/live_reporter.go (LiveSnapshotReporter implements
hub.PBSReporter via the cheap Client.Snapshots() list with last-known-good fallback,
bounded by an 8s timeout, list-only — never triggers a verify). Closes the gap where
the recipe's pbs block was omitted whenever the verify-loop SnapshotStore was empty
(one-shot collect + the first ~6h after a daemon restart). SnapshotStore.Get added
(per-datastore LKG). Wired into the collector in both runDaemon and runSelftestHub;
the verify loop keeps Recording into the SAME shared store via one hoisted pbsTargets.

v1 host-half drive shape: dropped drives[].role (hub/operator-owned manifest concept,
not host-derivable) and drives[].restic_repo_coord (named a backup tier that doesn't
exist). Drive shape is now {durable_id, mount_path, intent, fs_type?, total_bytes}.
Hub reads drives as json.RawMessage → no hub struct change; goldens re-pinned
byte-identical (agent + hub copies).

Tests: live_reporter_test.go (T1 load-bearing coord-without-verify + T2..T6),
TestDRRecipeHostHalf_V1DriveShape; each companion demonstrated to fail pre-fix then
reverted. go build/vet/test green.

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

internal/hub/testdata/host-report.golden.json

@@ -145,7 +145,6 @@
     "drives": [
       {
         "durable_id": "uuid:0fc63daf-8483-4772-8e79-3d69d8477de4",
-        "role": "",
         "mount_path": "/mnt/usb-backup",
         "intent": "enrolled",
         "total_bytes": 2000000000000