v0.114.0 — R-113: drive presence means the DEVICE, not the bind

BoundUnderParent, the one field the controller's drive-absent gate keys on,
reported only "is this path a mount target in the guest's mountinfo". The
drive's raw mount at /mnt/<name> is a systemd mount unit bound to its device and
dies with it, but the agent's own bind of <raw>/felhom-data under the shared
parent is an ordinary bind: nothing ties it to the device, so its mountinfo
entry OUTLIVES the device as a stale shell. Presence read that survivor as true,
planDriveGates never produced a Stop action, and nothing fired on any channel --
not backup_target_absent, not the generic storage_disconnected. Measured live in
E-2d: detached at 10:58:37Z, silent for 4.5 minutes while the agent itself
logged "enrolled drive absent by UUID" every 20s (felhom.eu
audits/E2D-fresh-vm-2026-07-29.md §5.2).

The fix: BoundUnderParent becomes a CONJUNCTION -- bound under the parent AND
the drive's raw host mount still mounted (devicePresent, new deviceCheck seam
defaulting to isHostMountpoint). Applied at BOTH /disks construction sites. The
union path matters more, not less: it hardcodes State:"attached", so the
raw-mount check is the only device truth that row carries, and it is exactly the
shape E-2d detached.

Why a conjunction and not a replacement: half 2 alone would regress boot
ordering, where the raw drive mounts early and the bind lands ~18s later; the
gate depends on that window reading ABSENT. The conjunction leaves that
byte-identical and closes only the case the gate could never see.

Unknown is never absent: devicePresent("") returns TRUE. A false absent stops a
working customer's apps -- the failure mode of this fix, not of the bug.

Controller UNCHANGED, no MinAgent bump. BoundUnderParent has exactly one
functional consumer (planDriveGates, intermediary.go:226); every other mention
in both repos is a comment or a test, and boot convergence deliberately moved
off it to pollLiveBinds/driveBindLive. The alternative -- a new DevicePresent
bool the controller ANDs in -- was rejected as dangerous: a bool absent from an
older agent's JSON decodes to false, so every drive on a pre-0.114.0 agent would
have read ABSENT and stopped its apps.

Tests +6 in internal/localapi (208 -> 214): groups A-D plus a wire-contract test
asserting the ENCODED bound_under_parent, since that is what crosses to the
controller. Four red-proofs run and reverted (drop the conjunction on each path;
invert unknown; drop the bind half); disks.go verified byte-identical after.

NOT LIVE-VALIDATED. No drive was pulled. Leg awaiting Session C: device loss ->
gate Stop -> SetDisconnected -> backup_target_absent on the wire.

REUSE.md

@@ -110,7 +110,8 @@
 | Anti-retarget durable-id binding | internal/localapi/wipe_reresolve.go | resolve id → re-derive + exact match → re-inspect expected state → act on RE-RESOLVED device only |
 | Atomic single-file JSON store | internal/storage/intent.go | `Open*` loads (missing=empty, corrupt=fail-loud), mutex, tmp+rename 0600, idempotent set |
 | Durable append-only log + index | internal/authz/noncestore.go (`FileNonceStore`) | fsync before returning "new"; replay into index on open; expiry-only compaction |
-| Injectable seam funcs on Server | internal/localapi/server.go (`reresolveWipe`, `deviceDurableID`, `boundCheck`, net-verify: `netTrigger`/`netMounted`/`netJournal`/`netReachable`) | prod default wired in `NewServer`; tests override — no real /dev, /proc/mounts, journalctl or TCP in tests |
+| Injectable seam funcs on Server | internal/localapi/server.go (`reresolveWipe`, `deviceDurableID`, `boundCheck`, `deviceCheck`, net-verify: `netTrigger`/`netMounted`/`netJournal`/`netReachable`) | prod default wired in `NewServer`; tests override — no real /dev, /proc/mounts, journalctl or TCP in tests |
+| `Server.devicePresent` (R-113, v0.114.0) | internal/localapi/disks.go | `devicePresent(rawMountPath) bool`; seam `deviceCheck`, default `isHostMountpoint` | the agent's DEVICE-presence signal — asks whether the drive's RAW mount is still mounted | **Use this, never the bind, to answer "is the drive there".** The raw mount is a device-bound systemd unit and dies with its device; the agent's own bind under the shared parent is NOT device-bound and outlives it as a stale shell. `BoundUnderParent` is now `boundUnderParent(...) && devicePresent(...)` at BOTH /disks construction sites — dropping either half is a regression with its own red-proof. Empty path ⇒ **true** (unknown is never absent: absent stops a customer's apps) |
 | Detached IN-MEMORY verify job (single slot, deliberately unpersisted) | internal/localapi/netverifyjob.go | claim slot sync (single-flight 409) → detached pipeline off baseCtx → auto-rollback on fail; restart ⇒ slot empty ⇒ the CALLER rolls back (Scenario F) — contrast formatjob (persisted+recovered) |
 | Optional dependency degradation | internal/localapi/server.go (`Options`) | nil dep ⇒ endpoint answers "not configured" (503), never a crash |
 | Version channel (v0.82.0) | internal/localapi/server.go (`Options.AgentVersion`; `Handler()` mux wrap) | sets `X-Felhom-Agent-Version` on EVERY response (all routes/statuses, incl. auth-fail/404) — the controller's capability-comparison source; empty version ⇒ header omitted |