docs: update documentatie voor app_volumes en tabs tree view

- CLAUDE.md: app_volumes.py in module-tabel, frontend tabs lijst, py_compile en smoke tests
- ARCHITECTURE.md: app_volumes.py in feature routers, py_compile en smoke tests
- API_GOLDEN.md: volumes endpoints gedocumenteerd (GET/POST/DELETE/prune/exists)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

contracts/API_GOLDEN.md

@@ -149,6 +149,74 @@ Golden example:
 }
 
 
+==================================================
+GET /api/volumes
+==================================================
+
+Curl:
+curl -s http://127.0.0.1:8081/api/volumes
+
+Response type:
+Array of Podman volume objects (raw Podman passthrough).
+
+Golden keys per item:
+- Name
+- Driver
+- Mountpoint
+- CreatedAt
+- Labels
+
+Golden example:
+[
+  {
+    "Name": "my-volume",
+    "Driver": "local",
+    "Mountpoint": "/home/kodi/.local/share/containers/storage/volumes/my-volume/_data",
+    "CreatedAt": "2026-03-01T12:00:00Z",
+    "Labels": {}
+  }
+]
+
+
+==================================================
+POST /api/volumes
+==================================================
+
+Request body (JSON):
+- name (string, required)
+- driver (string, optional, default "local")
+- labels (object, optional)
+- driverOpts (object, optional)
+
+Response: created volume object (raw Podman passthrough).
+
+
+==================================================
+DELETE /api/volumes/{name}
+==================================================
+
+Response on success (204 from Podman):
+{"ok": true}
+
+Error responses forwarded from Podman (e.g. 409 if in use).
+
+
+==================================================
+POST /api/volumes/prune
+==================================================
+
+Response: array of pruned volume names (raw Podman passthrough).
+
+
+==================================================
+GET /api/volumes/{name}/exists
+==================================================
+
+Response:
+{"exists": true}   — volume bestaat (Podman 204)
+{"exists": false}  — volume niet gevonden (Podman 404)
+
+
 ==================================================
 GET /api/openapi.json
 ==================================================