feat(config + admin panel): handle features activated

- review admin dashboard to reflect features enabled/disabled
- hide mount option if feature is disabled
- remove QUOTA option as it is not wired

example.env

@@ -387,9 +387,6 @@ DATABASE_URL=postgres://postgres:postgres@localhost:5432/oxicloud
 # Enable/disable authentication system (default: true)
 #OXICLOUD_ENABLE_AUTH=true
 
-# Enable per-user storage quotas (default: false)
-#OXICLOUD_ENABLE_USER_STORAGE_QUOTAS=false
-
 # Enable file/folder sharing (default: true)
 #OXICLOUD_ENABLE_FILE_SHARING=true
 
@@ -464,6 +461,37 @@ DATABASE_URL=postgres://postgres:postgres@localhost:5432/oxicloud
 # Set to false to prevent users from browsing the user directory.
 #OXICLOUD_EXPOSE_SYSTEM_USERS=true
 
+# External file mounts — surface host-filesystem paths (or a future
+# S3/WebDAV/SFTP backend) as folders inside a user's drive. Admins
+# configure mount rows via /api/admin/external-mounts (the "External
+# Mounts" tab in the admin panel); each row picks a target drive, a
+# name for the mount root, a provider kind, and a provider-specific
+# config (e.g. host path for local).
+#
+# When `false` (default):
+#   - Admin CRUD routes (/api/admin/external-mounts) are NOT
+#     registered — Axum returns 404. The admin panel's "External
+#     Mounts" tab is hidden from the sidebar too (FE gates on
+#     `serverConfig.features.external_mounts` — same discovery path
+#     as `message_bus`).
+#   - At boot, `MountRegistry` stays empty even if mount rows exist
+#     in the DB — the runtime resolver has nothing to route to.
+#     Users navigating into a mount-root folder see an empty native
+#     folder (row exists, no children).
+#
+# When `true`:
+#   - Admin panel exposes the CRUD; existing DB rows load at boot
+#     via `MountRegistry::reload`; users can browse mount contents.
+#
+# Opt-in per deployment because external mounts expose host
+# filesystems (or credentialed remote backends) inside user drives —
+# an admin misconfiguration can leak state that isn't part of
+# OxiCloud's normal storage substrate. Keep off unless you have a
+# concrete need.
+#
+# Default: false.
+#OXICLOUD_ENABLE_EXTERNAL_MOUNTS=false
+
 # ── People (face recognition) ────────────────────────────────────────────
 # Biometric data (GDPR Art. 9) — OFF by default, opt-in per deployment.
 # Detects faces and clusters them into people in the photo library.
@@ -1100,20 +1128,6 @@ OXICLOUD_WOPI_ENABLED=false
 # collaborative editor. See docs/plan/message-bus.md for the JSON-RPC 2.0
 # wire protocol.
 
-# Server-initiated protocol Ping interval (seconds). Prevents intermediate
-# proxies (Traefik, nginx, Cloudflare) and NAT boxes from reaping the TCP
-# session as idle. Read at each WS connect — a change takes effect on new
-# connections without restart. Set 0 (or any non-positive value) to fall
-# back to the default.
-#
-# Tuning: the interval should sit at most half the smallest hop's idle
-# timeout, so a single missed Ping doesn't kill the connection. Common
-# floors:
-#   * nginx `proxy_read_timeout` default 60s  → ping ≤ 30s
-#   * Cloudflare hard limit 100s              → ping ≤ 45s
-#   * Traefik with idleTimeout bumped to 3600s → 30s is safely under
-#OXICLOUD_MESSAGEBUS_KEEPALIVE_SECONDS=30
-
 # Message bus master switch. When `false`, /api/rt/ws and
 # POST /api/rt/ticket are NOT registered at boot — Axum returns 404
 # for both, keeping monitoring dashboards free of 5xx noise. Clients
@@ -1135,6 +1149,20 @@ OXICLOUD_WOPI_ENABLED=false
 # Default: true.
 #OXICLOUD_MESSAGEBUS_ENABLE=true
 
+# Server-initiated protocol Ping interval (seconds). Prevents intermediate
+# proxies (Traefik, nginx, Cloudflare) and NAT boxes from reaping the TCP
+# session as idle. Read at each WS connect — a change takes effect on new
+# connections without restart. Set 0 (or any non-positive value) to fall
+# back to the default.
+#
+# Tuning: the interval should sit at most half the smallest hop's idle
+# timeout, so a single missed Ping doesn't kill the connection. Common
+# floors:
+#   * nginx `proxy_read_timeout` default 60s  → ping ≤ 30s
+#   * Cloudflare hard limit 100s              → ping ≤ 45s
+#   * Traefik with idleTimeout bumped to 3600s → 30s is safely under
+#OXICLOUD_MESSAGEBUS_KEEPALIVE_SECONDS=30
+
 # -----------------------------------------------------------------------------
 # MEMORY ALLOCATOR TUNING (IMPORTANT FOR RAM USAGE)
 # -----------------------------------------------------------------------------