ux: add hidden folder hint, better path input placeholder, dialog titles

- Add info tooltip: 'Press Cmd+Shift+. in dialogs to show hidden folders'
- Better path input hint: 'Path to scan (e.g. ~/.claude/projects)'
- Add dialog titles for Load and Browse pickers
- Signed, notarized, stapled DMG

lib/screens/home/home_screen.dart

@@ -410,6 +410,7 @@ class _HomeScreenState extends State<HomeScreen> {
       final result = await FilePicker.platform.pickFiles(
         type: FileType.custom,
         allowedExtensions: ['jsonl'],
+        dialogTitle: 'Select a Claude session file (.jsonl)',
       );
       if (result != null && result.files.single.path != null) {
         await _loadFile(result.files.single.path!);
@@ -582,7 +583,7 @@ class _HomeScreenState extends State<HomeScreen> {
                     fontFamily: 'JetBrains Mono',
                   ),
                   decoration: InputDecoration(
-                    hintText: '~/.claude/projects',
+                    hintText: 'Path to scan (e.g. ~/.claude/projects)',
                     hintStyle: const TextStyle(
                       fontSize: 12,
                       color: AppColors.textMuted,
@@ -660,6 +661,11 @@ class _HomeScreenState extends State<HomeScreen> {
                 ),
               ),
             ),
+            const SizedBox(width: 8),
+            Tooltip(
+              message: 'Press Cmd+Shift+. in dialogs to show hidden folders',
+              child: Icon(Icons.info_outline, size: 14, color: AppColors.textMuted),
+            ),
           ],
         ),
       ],