chore(immich): drop the IMMICH_URL hook

A deployment no longer suggests an address for the first server: every
address is each account's own and is typed in the app, so the field opens
blank with a placeholder. The env var, its compose passthrough, the example
line and the `defaultUrl` field that carried it are all gone; the backend's
config route now answers with the saved list alone.

docker/frontend/src/Library.tsx

@@ -336,10 +336,6 @@ function Catalogue({ admin }: { admin: boolean }) {
   // A server is not a folder on the disk — see `engine/immich.ts` — so it is the
   // column's second source and the page holds no key of its own.
   const [servers, setServers] = useState<ImmichServer[]>([]);
-  // The address this deployment suggests for a first server — `IMMICH_URL`, which
-  // the backend answers with. Offered as a filled-in field, not as a saved row:
-  // it is a suggestion until a key is typed against it.
-  const [immichUrl, setImmichUrl] = useState('');
   const [addImmich, setAddImmich] = useState(false);
   const [editAlbums, setEditAlbums] = useState<LibraryFolder | null>(null);
   // The strip starts on the catalogue the last screen read: coming back from the
@@ -800,7 +796,6 @@ function Catalogue({ admin }: { admin: boolean }) {
       const config = await immichConfig();
       if (!alive) return;
       setServers(config.servers);
-      setImmichUrl(config.defaultUrl);
 
       // 5. Await photos reload if still running
       await reloadPromise;
@@ -1106,7 +1101,6 @@ function Catalogue({ admin }: { admin: boolean }) {
       // holds the key, and what it says is what the dialog will show next time.
       const config = await immichConfig(true);
       setServers(config.servers);
-      setImmichUrl(config.defaultUrl);
       if (!isNew && edited) {
         const next: LibraryFolder = { ...edited, albums: saved.albums };
         await putFolder(next);
@@ -3123,7 +3117,6 @@ function Catalogue({ admin }: { admin: boolean }) {
           it goes straight up to the backend, which probes it before it stores. */}
       {addImmich ? (
         <ImmichDialog
-          defaultUrl={immichUrl}
           onSaved={(saved, isNew) => void serverSaved(saved, isNew)}
           onClose={() => setAddImmich(false)}
         />
@@ -3131,7 +3124,6 @@ function Catalogue({ admin }: { admin: boolean }) {
       {editAlbums ? (
         <ImmichDialog
           server={servers.find((s) => s.id === editAlbums.server) ?? null}
-          defaultUrl=""
           onSaved={(saved, isNew) => void serverSaved(saved, isNew)}
           onClose={() => setEditAlbums(null)}
         />