v0.318.0: the internal data place, partitions, an honest whole-box backup offer (R-1084), sys_drive never offered (R-1082)

felhom.eu architecture/16 §4-§6 (build B). MinAgent 0.157.0 — the internal place and the partitions appear only when
agent >= 0.158.0 reports them. Tests red-proved; four parity fixtures refreshed (only the new lines).

Claude-Session: https://claude.ai/code/session_012qRErfCoiTkvDK9N5XHbzb

controller/README.md

@@ -3396,6 +3396,26 @@ no key into the household's account). Code: `internal/stacks/after_unclean_boot.
 - **Plex:** the claim code is an `after_start` field — asked on the Plex page once Plex runs (`POST /apps/plex/plex-claim`);
   the gate opens only when Plex says claimed, and „Kész" is refused before that.
 
+### 8d. Storage that knows its physical disks — the internal place, partitions (v0.317.0 build A, v0.318.0 build B)
+
+Design: felhom.eu `architecture/16-storage-physical-identity.md`. The host agent decides which physical disk a place sits on;
+the controller only asks.
+
+- **Second copies** (v0.317.0): Tier-2 and the one-copy notice ask the agent (`POST /disks/same-disk`); a copy counts only on a
+  proven different disk. **The whole-box backup offer** (v0.318.0, R-1084) does the same: proven different → the disk-failure
+  promise; unproven (a VM) → offered without the promise (`backup.target.offer_unproven`); same disk → not offered.
+- **The internal data place „Belső tárhely"** (v0.318.0, agent ≥ 0.158.0): a volume on the system disk that the installer (or
+  the operator's signed `add_internal_place`) makes on a one-disk box. When the agent reports it (`GET /disks`, kind
+  `internal`), the drive-gate tick binds it into the guest and, on the next tick, registers it as a drive of kind `internal`
+  — the default drive unless the household has one. Media and data-folder apps then install with no extra step. Eject,
+  retire and format are refused (`err.web.belso_tarhely_eletciklus`); moving its data to another drive is allowed.
+- **Partitions** (v0.318.0, agent ≥ 0.158.0): the format and attach wizards list each part of a free disk — „format this
+  part" (empty, or with data through the typed confirmation) and „use this part" (an ext4/xfs filesystem). A disk whose other
+  part is already a drive offers only its free parts; formatting that whole disk is refused on the server too. No part is
+  ever created, deleted or resized from the dashboard (`16` D5).
+- **`/mnt/sys_drive` is never offered to attach** (v0.318.0, R-1082): it rides in every whole-box copy. A box that already
+  registered it keeps it.
+
 ### 9. Central Hub Reporting
 
 #### Operator actions (`internal/report/opactions.go`, `09` §3 decision 185)