fix(offline): replace blocking overlay with slim banner; add server settings link (#170)

When offline with no cached content, the full-screen OfflineOverlay blocked
all navigation including Settings, making it impossible to fix a broken
server config. Replace it with the same slim banner used in offline-cache mode.

- OfflineBanner now handles both cases: cache (existing) and no-cache (new)
- No-cache banner shows server name and a direct link to Settings → Server tab
- OfflineOverlay component is no longer used (import removed from App.tsx)
- All 8 locales: added offlineNoCacheBanner and serverSettings keys

Fixes #170

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

src/App.tsx

@@ -45,7 +45,6 @@ import { DragDropProvider } from './contexts/DragDropContext';
 import TooltipPortal from './components/TooltipPortal';
 import ConnectionIndicator from './components/ConnectionIndicator';
 import LastfmIndicator from './components/LastfmIndicator';
-import OfflineOverlay from './components/OfflineOverlay';
 import OfflineBanner from './components/OfflineBanner';
 import OfflineLibrary from './pages/OfflineLibrary';
 import Genres from './pages/Genres';
@@ -341,17 +340,10 @@ function AppShell() {
             {isQueueVisible ? <PanelRightClose size={18} /> : <PanelRight size={18} />}
           </button>
         </header>
-        {connStatus === 'disconnected' && hasOfflineContent && (
-          <OfflineBanner onRetry={connRetry} isChecking={connRetrying} />
+        {connStatus === 'disconnected' && (
+          <OfflineBanner onRetry={connRetry} isChecking={connRetrying} showSettingsLink={!hasOfflineContent} serverName={serverName} />
         )}
         <div className="content-body" style={{ padding: 0, position: 'relative' }}>
-          {connStatus === 'disconnected' && !hasOfflineContent && (
-            <OfflineOverlay
-              serverName={serverName}
-              onRetry={connRetry}
-              isChecking={connRetrying}
-            />
-          )}
           <Routes>
             <Route path="/" element={<Home />} />
             <Route path="/albums" element={<Albums />} />