rewire 2026-08-11: single-mount NFS architecture

- topology.svg, container-tree.svg, data-flow.svg: show /srv/nc-files
  bound directly into nextcloud container at /mnt/ncdata (no
  intermediate /mnt/nc-data/nextcloud-data layer).
- architecture.html: explain rewire, update storage table, remove
  pre-rewire 'why two layers' section.
- procedure.html: NEXTCLOUD_DATADIR=/srv/nc-files, no mastercontainer
  bind, add §2.5 Rewire 2026-08-11 with recovery procedure,
  update backup script to also tar local nextcloud app volume,
  fix 4.3 verification (302 -> /login, status.php, file visibility).
- operations.html: 4 backup files now (added aio-nextcloud-app.tar.gz),
  restore procedures updated, single-file restore uses new tar layout.
- troubleshooting.html: add 3 new sections — appdata-missing,
  nextcloud-not-spawning, collabora-discovery-warning.
- request-flow.svg: remove nextcloud/ subdir from NFS write path.
- index.html, README.md: update paths and metadata.

assets/diagrams/request-flow.svg

@@ -99,7 +99,7 @@
   <rect x="920" y="465" width="160" height="60" rx="4" class="ok"/>
   <text x="1000" y="485" text-anchor="middle" class="lbl" fill="#9d7ad9">NFS write</text>
   <text x="1000" y="503" text-anchor="middle" class="lbl-tiny" fill="#9d7ad9">→ /slab/container_storage/office/</text>
-  <text x="1000" y="518" text-anchor="middle" class="lbl-tiny" fill="#9d7ad9">nextcloud/admin/files/</text>
+  <text x="1000" y="518" text-anchor="middle" class="lbl-tiny" fill="#9d7ad9">admin/files/</text>
 
   <!-- 10. 201 Created returned -->
   <rect x="20" y="555" width="160" height="50" rx="4" class="ok"/>
@@ -134,5 +134,5 @@
   <text x="550" y="681" text-anchor="middle" class="lbl-sm" fill="#d9a96b">Tip: WOPI (Collabora file open) follows a parallel path — browser iframe → apache → nextcloud PHP → wopi URL → apache proxy → collabora → WOPI read</text>
   <text x="550" y="694" text-anchor="middle" class="lbl-tiny" fill="#d9a96b">the WOPI URL is verified as http://nextcloud-aio-apache.nextcloud-aio:23973 (internal docker network only)</text>
 
-  <text x="1060" y="715" text-anchor="end" class="lbl-tiny">2026-08-10 · nextcloud_office</text>
+  <text x="1060" y="715" text-anchor="end" class="lbl-tiny">2026-08-11 · nextcloud_office · rewire</text>
 </svg>