docs: follow the storage move from nuc/USB to nas/SATA

backup-strategy (the entry point) still described nuc pulling the ks4
replicas: the leg, its WireGuard peer and the target pool now live on
nas with the 4 TB on direct SATA. Also: ks4 README flow chart redrawn
for the new topology, incus-copy leg 2 retargeted, usb4t-dropouts
marked RESOLVED (kept for the diagnosis method and the alerting gap),
and ks2/plan records that the interim push was deliberately not
re-enabled.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

ks2/plan.md

@@ -18,10 +18,14 @@ What remains on the box is **cold history**: instance replicas on pool
 snapshotted daily there (`zfs-auto-snapshot.sh`, 2-month expiry).
 
 ⚠️ While the nas leg waits for FTTH, instances have no *fresh*
-off-site copy — the ks2 push is to be re-enabled as soon as the
-initial restic sync finishes (decided 2026-08-28), and retired again
-when nas takes over. (The leg moved from nuc to the new host `nas`
-on 2026-08-30 — see [nas-seed.md](nas-seed.md).)
+off-site copy. The ks2 push was **deliberately not re-enabled**
+(2026-08-30): ks2's replicas are three weeks old, its `data` pool is
+94 % full, no common snapshot survives ks4's 7-day expiry, and the box
+is wiped within the month — so a full ~1.5 T re-send buys four weeks
+of freshness on hardware already scheduled for destruction. Off-site
+protection meanwhile rests on `restic-data` (data, databases and the
+incus configuration — enough to rebuild). (The leg moved from nuc to
+the new host `nas` on 2026-08-30 — see [nas-seed.md](nas-seed.md).)
 
 ## Inventory findings (2026-08-22)
 
@@ -53,7 +57,7 @@ on 2026-08-30 — see [nas-seed.md](nas-seed.md).)
 | off-site, S3 (data+DB) | **restic** → bucket `restic-data` ([restic-backup.md](../ks4/restic-backup.md)) | **live** (05:00) |
 | off-site, S3 (instances) | restic over `incus file mount` of the `backup`-project replicas | **shelved** 2026-08-28 (replication covers instances) |
 | off-site, nas | **nas** pulls `ks4:*` → pool `ks4backup` over WG ([nas-seed.md](nas-seed.md)) | waiting FTTH (< Sep 30); moved off nuc 2026-08-30 |
-| off-site, ks2 (interim) | `incus-copy.sh -d ks2 -m push` at 02:00 until the nas leg seeds | to re-enable once the restic seed finishes |
+| off-site, ks2 (interim) | `incus-copy.sh -d ks2 -m push` | **not re-enabled** 2026-08-30 — see above |
 
 ## Actions (backup work documented in [`../ks4/`](../ks4/), ks2-only tasks here)