refactor(auth): E.44 — extract server-profile + lastfm + audio-settings factories (#609)

Three action-factories peel ~25 setters out of the authStore body,
following the playerStore action-factory pattern from Phase E:

- `createServerProfileActions` — `addServer`, `updateServer`,
  `removeServer` (the non-trivial one — drops every per-server map
  entry for the removed id), `setServers`, `setActiveServer`,
  `setLoggedIn`, `setConnecting`, `setConnectionError`, `logout`.
- `createAuthLastfmActions` — credentials + session connect/disconnect
  + error flag + master scrobbling toggle. Network calls (love /
  scrobble) stay in the playerStore-side `lastfmActions.ts`.
- `createAudioSettingsActions` — replay-gain / normalization /
  loudness mode toggles (each calls `usePlayerStore.getState()
  .updateReplayGainForCurrentTrack()` so a running track catches up),
  plus crossfade / gapless / hi-res / audio-output (no engine
  callback needed).

Pure code-move; no behaviour change. authStore.ts: 518 → 428 LOC (−90).

src/store/authServerProfileActions.ts

@@ -0,0 +1,69 @@
+import type { AuthState } from './authStoreTypes';
+import { generateId } from './authStoreHelpers';
+
+type SetState = (
+  partial: Partial<AuthState> | ((state: AuthState) => Partial<AuthState>),
+) => void;
+
+/**
+ * Server profile + connection lifecycle. `removeServer` is the
+ * non-trivial one: when the active server is the one being removed it
+ * also drops every per-server map entry tied to that id and switches
+ * the active id to the next available server (or null) so the rest of
+ * the app doesn't end up reading stale state.
+ */
+export function createServerProfileActions(set: SetState): Pick<
+  AuthState,
+  | 'addServer'
+  | 'updateServer'
+  | 'removeServer'
+  | 'setServers'
+  | 'setActiveServer'
+  | 'setLoggedIn'
+  | 'setConnecting'
+  | 'setConnectionError'
+  | 'logout'
+> {
+  return {
+    addServer: (profile) => {
+      const id = generateId();
+      set(s => ({ servers: [...s.servers, { ...profile, id }] }));
+      return id;
+    },
+
+    updateServer: (id, data) => {
+      set(s => ({
+        servers: s.servers.map(srv => srv.id === id ? { ...srv, ...data } : srv),
+      }));
+    },
+
+    removeServer: (id) => {
+      set(s => {
+        const newServers = s.servers.filter(srv => srv.id !== id);
+        const switchedAway = s.activeServerId === id;
+        const { [id]: _r, ...entityRatingRest } = s.entityRatingSupportByServer;
+        const { [id]: _a, ...audiomuseRest } = s.audiomuseNavidromeByServer;
+        const { [id]: _idn, ...identityRest } = s.subsonicServerIdentityByServer;
+        const { [id]: _iss, ...issueRest } = s.audiomuseNavidromeIssueByServer;
+        const { [id]: _pr, ...probeRest } = s.instantMixProbeByServer;
+        return {
+          servers: newServers,
+          activeServerId: switchedAway ? (newServers[0]?.id ?? null) : s.activeServerId,
+          isLoggedIn: switchedAway ? false : s.isLoggedIn,
+          entityRatingSupportByServer: entityRatingRest,
+          audiomuseNavidromeByServer: audiomuseRest,
+          subsonicServerIdentityByServer: identityRest,
+          audiomuseNavidromeIssueByServer: issueRest,
+          instantMixProbeByServer: probeRest,
+        };
+      });
+    },
+
+    setServers: (servers) => set({ servers }),
+    setActiveServer: (id) => set({ activeServerId: id, musicFolders: [] }),
+    setLoggedIn: (v) => set({ isLoggedIn: v }),
+    setConnecting: (v) => set({ isConnecting: v }),
+    setConnectionError: (e) => set({ connectionError: e }),
+    logout: () => set({ isLoggedIn: false, musicFolders: [] }),
+  };
+}