fix(studio): localize sidebar tooltips that stayed English

The connection-row tooltip, the _ConnectionLabel caption,
the footer settings tooltip, and the channel-pill explainer
were hardcoded English even when the running app was set to
German. Move all four through AppLocalizations.

Adds ARB strings (de + en):
 - connectionTapToStart      antippen zum Starten  / tap to start
 - sidebarSettingsTooltip    Einstellungen (Cmd-;) / Settings (Cmd-;)
 - sidebarChannelTooltip     multi-line channel explainer

Existing connectionConnected / connectionUnreachable /
connectionConnecting are reused as the caption pieces; only
those two new strings (plus the channel tooltip) needed
adding.

Version 0.51.7 -> 0.51.8.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/main.dart

@@ -27,7 +27,7 @@ import 'widgets/widgets.dart';
 /// Studio's own build version. Bump on every UI commit so the
 /// running app self-identifies — visible in the sidebar header
 /// and quick-glance proof that you're seeing the current build.
-const String kStudioVersion = '0.51.7';
+const String kStudioVersion = '0.51.8';
 
 Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();
@@ -547,29 +547,35 @@ class _SidebarState extends State<_Sidebar>
                   // disconnected fires the daemon-start action,
                   // so we can drop the inline "Start hub" button
                   // that used to make this row's height balloon.
-                  SizedBox(
-                    height: _connRowH,
-                    child: _sidebarRow(
-                      leading: Tooltip(
-                        message: widget.connected == true
-                            ? 'Connected · ${widget.endpointLabel}'
-                            : widget.connected == false
-                                ? 'Disconnected · tap to start · ${widget.endpointLabel}'
-                                : 'Connecting · ${widget.endpointLabel}',
-                        child: _CollapsedConnectionDot(
-                          connected: widget.connected,
+                  Builder(
+                    builder: (context) {
+                      final l = AppLocalizations.of(context)!;
+                      final caption = widget.connected == true
+                          ? l.connectionConnected
+                          : widget.connected == false
+                              ? l.connectionTapToStart
+                              : l.connectionConnecting;
+                      return SizedBox(
+                        height: _connRowH,
+                        child: _sidebarRow(
+                          leading: Tooltip(
+                            message: '$caption · ${widget.endpointLabel}',
+                            child: _CollapsedConnectionDot(
+                              connected: widget.connected,
+                            ),
+                          ),
+                          label: _ConnectionLabel(
+                            connected: widget.connected,
+                            endpoint: widget.endpointLabel,
+                          ),
+                          t: t,
+                          labelsInteractive: labelsInteractive,
+                          onTap: widget.connected == false
+                              ? () => _startDaemon(context)
+                              : null,
                         ),
-                      ),
-                      label: _ConnectionLabel(
-                        connected: widget.connected,
-                        endpoint: widget.endpointLabel,
-                      ),
-                      t: t,
-                      labelsInteractive: labelsInteractive,
-                      onTap: widget.connected == false
-                          ? () => _startDaemon(context)
-                          : null,
-                    ),
+                      );
+                    },
                   ),
                   const SizedBox(height: _rowGap),
                   // Channel row — fixed 28px. Always reserved
@@ -732,10 +738,9 @@ class _ChannelPill extends StatelessWidget {
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
     final accent = _accent(theme.colorScheme);
+    final l = AppLocalizations.of(context)!;
     return Tooltip(
-      message:
-          'Active channel — click to switch in Settings (⌘;).\n'
-          'production = stable · beta = pre-release · dev = rolling · local = workspace',
+      message: l.sidebarChannelTooltip,
       child: Material(
         color: theme.colorScheme.surfaceContainerHigh,
         borderRadius: BorderRadius.circular(FaiRadius.sm),
@@ -905,14 +910,15 @@ class _ConnectionLabel extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
+    final l = AppLocalizations.of(context)!;
     final captionColor = connected == false
         ? theme.colorScheme.error
         : theme.colorScheme.onSurface;
     final caption = connected == true
-        ? 'connected'
+        ? l.connectionConnected
         : connected == false
-            ? 'tap to start'
-            : 'connecting…';
+            ? l.connectionTapToStart
+            : l.connectionConnecting;
     return Column(
       mainAxisAlignment: MainAxisAlignment.center,
       crossAxisAlignment: CrossAxisAlignment.start,
@@ -1076,6 +1082,7 @@ class _Footer extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    final l = AppLocalizations.of(context)!;
     return Row(
       crossAxisAlignment: CrossAxisAlignment.center,
       children: [
@@ -1084,7 +1091,7 @@ class _Footer extends StatelessWidget {
           child: Center(
             child: IconButton(
               icon: const Icon(Icons.settings_outlined, size: 16),
-              tooltip: 'Settings (⌘;)',
+              tooltip: l.sidebarSettingsTooltip,
               visualDensity: VisualDensity.compact,
               onPressed: onOpenSettings,
             ),