REPORT + CONTEXT + REUSE: R-185 closed, with the corrected root cause

The installer defect was NOT PVE_STORAGES as the row and the task assumed: the
create arm of configure_backup_target grants, the Scenario-F reuse arm did not.
Also records the measured trap (an ungranted path answers with INHERITED
privileges, not empty and not 403), the deviation from the spec's suggested
Prober generalisation in favour of the existing poolReadStatus precedent, the
hollow test caught before it shipped, and that demo-hp carried the same drift and
was fixed.

CONTEXT.md

@@ -5,6 +5,34 @@
 
 ## Current
 
+- **2026-08-03 — v0.123.0 (R-185): a tier the box cannot READ now says so.** The agent's token had
+  `FelhomAgentStore` on `local`, `local-lvm`, `felhom-pbs` and **not** on `felhom-backup` — the
+  storage both demo boxes configure as `local_backup_target`. That storage answered `{"data":[]}`
+  through the token while root listed three archives, and `pickForThisRun` skipped it as *"no settled
+  archive yet"* — **which is what a brand-new tier reports**, so the host tier was never
+  restore-testable and nothing said so.
+  - **The permission question is asked directly**, because unlike the listing it has a definite
+    answer: `Client.Permissions` reads `/access/permissions?path=/storage/<target>` **as the agent's
+    own token**, and `storeGrantStatuses` emits one `capability.Status` per configured tier. It
+    composes AROUND the sudo prober, the way `poolReadStatus` already does — an API read does not
+    belong inside a sudo-policy probe. `Status`'s wire shape is untouched, so the hub's critical
+    degraded alert applies with **no hub change**.
+  - **MEASURED FIRST, and the obvious reading is wrong:** an ungranted path answers neither empty nor
+    403 — it carries the privileges INHERITED from the box-wide `/` grant
+    (`Sys.Audit, SDN.Use, Datastore.Audit`). Checking path-presence, or `Datastore.Audit`, reports a
+    blinded storage HEALTHY. The probe tests **`Datastore.AllocateSpace`**; re-measure before ever
+    changing that constant (`storeGrantRequiredPriv`, red-proved).
+  - **The probed set comes from `BackupTiers()`, never a fixed list** — a hardcoded probe list is the
+    defect reproduced inside the fix. Critical, EXCEPT the `local` fallback target (reported, but it
+    does not page). It never consults content, so it cannot alarm on a newborn tier; it never reports
+    ok when it could not ask.
+  - **LIVE:** degraded observed on the still-blind box (hub emailed `agent_capability_degraded`) →
+    grant applied on **both** demo boxes → token lists 3 and 4 archives → `ok=70 total=70 degraded=0`
+    and `degraded → ok` at the hub → **the host tier became a due-check candidate for the first time**,
+    correctly picking the 08-02 archive (08-03 had not settled 24 h).
+  - **The installer's real defect was NOT `PVE_STORAGES`** — see `felhom.eu` CONTEXT S-22: Case A
+    grants, the Scenario-F reuse arm did not. Fixed in installer **1.24.0** with a gate.
+
 - **2026-08-03 — v0.122.0 (R-189 · R-188 · R-186): three signals that lied about their own work.**
   None touches data; all three cost attention, which every other signal depends on.
   - **R-189 — a passing restore-test no longer vanishes on a restart.** `restore_tests[]` came only