feat(ui): replace the Pinned sidebar section with an Apps entry

The sidebar no longer lists pinned add-ons. It shows one Apps entry that
opens the add-ons drawer, with a Show all link below it that opens the
same drawer. Pins are used from the drawer, where a pinned tile keeps
its pin and move buttons. The server pins API is unchanged.

Remove the PinnedNav component and its locale title, rename the
items.addons label to Apps, and update the e2e specs and the add-ons
documentation to match.

Assisted-by: Claude Code:claude-sonnet-5-5 playwright
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

docs/content/features/addons.md

@@ -1662,6 +1662,8 @@ sent with `Cache-Control: private, no-store`.
 
 ### Pins
 
+Pins no longer appear in the sidebar. They are used from the add-ons drawer: a pinned tile there has buttons to move it earlier or later.
+
 `GET /api/addons/pins` returns the caller's pinned add-on IDs as a JSON array, in order.
 `PUT /api/addons/pins` takes a JSON array of add-on IDs, replaces the caller's pins with it
 and returns the saved list. Both routes need an authenticated caller. They need no
@@ -1709,11 +1711,11 @@ reach **Browse**, **Installed** and **Libraries** from the drawer. The tabs are
 convenience: the owner checks administration again on every call, so a request that skips
 the page is denied the same way (403).
 
-The sidebar has four items: **Chat**, **Models**, **Add-ons** and **Settings**. Below them
-a **Pinned** section lists the add-ons the user pinned, in the order the user chose. Pins
-belong to the user, follow the user across browsers, and are capped at eight in the
-sidebar. A pin whose add-on is stopped is muted and opens the detail view; a pin whose
-add-on was removed or is hidden is not drawn. An empty section is not drawn. Operators who
+The sidebar has the items **Chat**, **Models** and **Apps**, and below Apps a **Show all**
+link. Both open the add-ons drawer at `/app/addons`. Pins no longer appear in the sidebar:
+the user pins add-ons and changes their order with the buttons on a pinned tile in the drawer. Pins belong to the user, follow the user across browsers, and are
+capped at eight. A pin whose add-on is stopped opens the detail view; a pin whose add-on
+was removed or is hidden is not drawn. Operators who
 need the previous sidebar can set `LOCALAI_LEGACY_NAVIGATION=true` (flag
 `--legacy-navigation`); it also brings back the Add-ons tab of the Build hub, which then opens `/app/addons`. The switch is a rollback aid and is removed one release after the
 new navigation ships; the UI reads it from the `addon_navigation` key of `/api/features`.