R-108: network storage may not host an app's data namespace (v0.187.0)

This is D5's precondition and it is now met.

An app's namespace root IS its backup root: namespaceRoot returns a non-system
drive path as-is, so the recovery unit lands at <HDD_PATH>/backups/primary/<stack>/.
On a NAS that sits inside the share, which FileBrowser binds WHOLE — share root,
:rslave, download:true.

The bind was NOT narrowed, and establishing why inverted the fix. The share-root
:rslave bind is load-bearing (a 2026-07-22 probe proved an in-container access
through it wakes the idle automount trigger), and scoping is undefinable anyway:
apps on a share store at <share>/<app>, there is no userdata/ layer, and creating
one would write Felhom convention onto a customer's own NAS, which R-67 forbids.
So the browsing surface cannot be narrowed and the backup tree must never be
placed under it. Operator ruling: refuse the placement, keep the browse bind.
Tier 2 already refuses network targets for this reason (F-6C-1).

Nothing stranded: zero apps on network storage across all six hub customers
including Peti. R-67's browse capability is byte-identical.

FIVE surfaces, not the four the register named — settings.RefuseAsAppNamespace is
the single predicate. The deploy POST is the real boundary (it accepts any
caller-supplied HDD_PATH; DeployStack validates only os.Stat). Surface 4,
handleStorageDecommission mode=migrate, guarded only its SOURCE, so a whole
namespace could be decommissioned ONTO a NAS — that one is not in the register.

Fails closed: /mnt/felhom-drives holds both kinds, Kind exists only on a
registered path, so an unregistered path under that root refuses.

Supersedes README's "NAS backup locality — decision A" (v0.118.0).

9 tests, all non-effect (nil stackMgr, so a guard that misses panics rather than
passing). 4 red-proofs, each mutation asserted to have landed.
Suite rc=0, 27 packages, 0 FAIL. vet rc=0. Template + emoji gates OK.

REUSE.md

@@ -230,6 +230,7 @@
 | `Server.sambaAddrFn` (func seam) | controller/internal/web/server.go (field) + sharing_handlers.go `sambaLANAddress()` | nil → `stackMgr.SambaLANAddress()` | The web-side half of the connect card. Tests inject a COUNTED fn — the fresh-per-render assertion is what stops anyone memoizing a DHCP lease |
 | `Manager.guestNetExecFn` (func seam) + `GuestGateway()` / `GuestNetSnapshot()` | controller/internal/stacks/manager.go (field) + guestnet.go | nil → `docker exec felhom-samba <args>` — ONE seam for all R-66 guest-netns reads (route/link/addr/resolv.conf); tests script canned outputs per argv | guestnet_test.go. **The netns door rule:** the controller's OWN netns is the docker bridge, so any in-process read (`net.Interfaces`, `/proc/net/route`, its own `/etc/resolv.conf` = 127.0.0.11) is the S-2 wrong answer — guest-net reads MUST go through the samba (`network_mode: host`) exec door. Megosztás off ⇒ door closed ⇒ "" / per-item error strings; NEVER substitute an in-process value. Same S-5 law as SambaLANAddress: live per render, never cached/persisted. Parsers (`parseDefaultRoute`, `parseGuestInterfaces`, `parseResolvConf`) are pure + separately pinned |
 | `buildFileBrowserPaths` + `fbPathDeps` (R-67, v0.160.0) | controller/internal/web/handlers.go | pure assembly of one FileBrowser sync pass: (mount lines, config source paths) from the registry, with per-kind gates | filebrowser_network_test.go. **Two storage classes, two DIFFERENT gates:** drives keep the drive-absent gate + userdata scoping + skeleton (byte-identical to pre-R-67 — tested); network shares bind the share ROOT `:rslave` with the STUB gate instead (`classifyFSPath`; stub ⇒ excluded from mounts AND sources — an exposed stub swallows uploads the real mount later shadows; idle autofs / unknown ⇒ include, fail open). NEVER call `EnsureUserdataSkeleton` toward a network path (red-proven); never force-wake an idle trigger in the sync (doctrine) |
+| `Settings.RefuseAsAppNamespace` (R-108, v0.187.0) | controller/internal/settings/settings.go | `(path) (refuse bool, hungarianReason string)` — may an app's DATA NAMESPACE live here? | **THE single predicate for every placement surface** (deploy POST `api/router.go`, per-app migrate list + `handleStorageMigrateApp`, `handleStorageDecommission` mode=migrate TARGET). **Network storage is refused** because an app's namespace root IS its backup root (`namespaceRoot` returns a non-system drive path as-is → `<HDD_PATH>/backups/primary/<stack>/`), and on a share that lands inside FileBrowser's share-ROOT `download:true` bind — which CANNOT be narrowed (R-67 `:rslave` = automount wake; and apps on a share store at `<share>/<app>`, so there is no `userdata/` to scope to and creating one would write Felhom convention onto a customer's NAS). **DISTINCT from `refuseNetworkLifecycle`** — that asks "may a DRIVE lifecycle op run on this path" and is applied to the op's SUBJECT; this asks "may an app live here" and is applied to a placement TARGET. Migrate needs BOTH. **FAILS CLOSED:** `/mnt/felhom-drives` holds both kinds, so a path prefix cannot classify — `Kind` exists only on a REGISTERED path, therefore an unregistered path under that root is un-classifiable and REFUSES. Empty path = SSD-resident = allowed; nil receiver refuses. network_app_namespace_test.go, 4 red-proofs |
 | `Server.guestGatewayFn` / `guestNetFn` (func seams) | controller/internal/web/server.go (fields) + sharing_handlers.go accessors | nil → `stackMgr.GuestGateway` / `stackMgr.GuestNetSnapshot` | network_card_test.go — the counted-fn freshness test (2 renders ⇒ 2 resolves) is what stops anyone memoizing a DHCP lease; the Hálózati név row is gated on `smb.Enabled` (red-proven: gate dropped ⇒ \\FELHOM rendered while samba is down) |
 | `sambaEnsureState.consumeIfRunning()` | controller/internal/web/samba_ensure_job.go | serve-once `snapshot()` for terminal `running` only | `/sharing/status` carries a job EDGE (`phase`) and a service LEVEL (`running`) in one envelope — never let a level reach the phase channel, and never re-serve a consumed edge: the client answers `phase=="running"` with `location.reload()`, so both mistakes produce an infinite page reload (S-1/S-4, DIAG-sharing-2026-07-20.md). `failed`/`needs_password`/in-flight are NOT consumed |
 | `infra.SambaHostInterface` | controller/internal/infra/samba.go | the guest LAN nic name (`eth0`) | Single source for smb.conf's `interfaces =`, the container's `FELHOM_IFACE`, and the LAN-address read — if they name different nics, the service and the address the page prints drift apart |