feat: keyboard shortcuts in remote sessions

Add an opt-in keyboard-shortcut system that triggers session
actions (Send Ctrl+Alt+Del, Toggle Fullscreen, Switch Display,
Screenshot, Switch Tab, etc.) via three-modifier combinations
during a remote session.

Architecture
- Native: src/keyboard/shortcuts.rs intercepts at the encoder
  layer (process_event and process_event_with_session), so the
  feature is input-source-independent. Bindings persist as a
  single JSON blob in LocalConfig.
- Web: matching + keydown intercept live in the separate hand-
  written TS client at flutter/web/js/ (gitignored, not in this
  repo). flutter/lib/web/bridge.dart::mainInit registers
  window.onShortcutTriggered so the JS matcher can dispatch
  back into the active session's ShortcutModel; the bridge's
  mainReloadKeyboardShortcuts forwards to a JS reloadShortcuts
  on settings writes.
- Three-modifier prefix (Ctrl+Alt+Shift; Cmd+Option+Shift on
  macOS/iOS) sidesteps the need for a pass-through toggle.
- Flutter native path threads the explicit per-call SessionID
  for tab-precise routing; rdev path uses globally-current
  session.

UI
- Settings -> General -> Keyboard Shortcuts opens a dedicated
  configuration page; desktop and mobile share a body widget.
- Recording dialog with live capture, prefix validation, and a
  conflict-replace flow.
- Toolbar menu items display the bound shortcut inline.
- Default bindings (adapted from AnyDesk):
    +Del    Send Ctrl+Alt+Del
    +Enter  Toggle Fullscreen
    +Left/Right  Switch Display Prev/Next
    +P      Screenshot
    +1..9   Switch Session Tab

Other
- AGENTS.md: documented (a) flutter_rust_bridge_codegen needs
  a pinned version + Dart bridge wrappers should be hand-
  written, and (b) the Web-target split where flutter/web/js/
  is the runtime owner on Web rather than wasm-compiled Rust.
- 38 new i18n strings in src/lang/en.rs with Chinese
  translations in src/lang/cn.rs.

Refs discussion #1933.

flutter/lib/mobile/pages/mobile_keyboard_shortcuts_page.dart

@@ -0,0 +1,95 @@
+// flutter/lib/mobile/pages/mobile_keyboard_shortcuts_page.dart
+//
+// Mobile shell for the Keyboard Shortcuts configuration page. Mirrors
+// `desktop/pages/desktop_keyboard_shortcuts_page.dart` but with a touch-
+// friendly layout (ListTile rows instead of dense rows) and a hint banner
+// that explains the recording flow only works with a physical keyboard.
+//
+// All actual logic — group definitions, JSON I/O, conflict-replace flow,
+// recording-dialog round-trip, "Reset to defaults" — lives in the shared
+// `common/widgets/keyboard_shortcuts/page_body.dart`. This file only
+// supplies the AppBar, the AppBar action, and the platform hint banner.
+//
+// Mobile keyboard detection limitation: Flutter has no reliable
+// "is a physical keyboard attached?" API on iOS or Android. Soft keyboards
+// don't generate the `KeyDownEvent`s the recording dialog listens for, so
+// in practice the dialog only does anything useful when the user actually
+// has a hardware keyboard plugged in (USB / Bluetooth / Smart Connector).
+// For V1 we don't try to detect attachment — we just surface the
+// requirement as an in-page hint instead of disabling the Edit button.
+
+import 'package:flutter/material.dart';
+
+import '../../common.dart';
+import '../../common/widgets/keyboard_shortcuts/page_body.dart';
+
+class MobileKeyboardShortcutsPage extends StatefulWidget {
+  const MobileKeyboardShortcutsPage({Key? key}) : super(key: key);
+
+  @override
+  State<MobileKeyboardShortcutsPage> createState() =>
+      _MobileKeyboardShortcutsPageState();
+}
+
+class _MobileKeyboardShortcutsPageState
+    extends State<MobileKeyboardShortcutsPage> {
+  final GlobalKey<KeyboardShortcutsPageBodyState> _bodyKey = GlobalKey();
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    return Scaffold(
+      appBar: AppBar(
+        title: Text(translate('Keyboard Shortcuts')),
+        actions: [
+          IconButton(
+            tooltip: translate('Reset to defaults'),
+            onPressed: () =>
+                _bodyKey.currentState?.resetToDefaultsWithConfirm(),
+            icon: const Icon(Icons.restore),
+          ),
+        ],
+      ),
+      body: KeyboardShortcutsPageBody(
+        key: _bodyKey,
+        compact: false,
+        editButtonHint: translate('shortcut-mobile-physical-keyboard-tip'),
+        headerBanner: _PhysicalKeyboardHintBanner(theme: theme),
+      ),
+    );
+  }
+}
+
+/// A muted info banner shown above the master toggle on mobile. We can't
+/// reliably detect whether a physical keyboard is attached, so instead of
+/// disabling the Edit button we surface the requirement up front.
+class _PhysicalKeyboardHintBanner extends StatelessWidget {
+  final ThemeData theme;
+  const _PhysicalKeyboardHintBanner({required this.theme});
+
+  @override
+  Widget build(BuildContext context) {
+    final color = theme.colorScheme.primary.withOpacity(0.08);
+    return Container(
+      padding: const EdgeInsets.all(12),
+      decoration: BoxDecoration(
+        color: color,
+        borderRadius: BorderRadius.circular(8),
+      ),
+      child: Row(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          Icon(Icons.info_outline,
+              size: 18, color: theme.colorScheme.primary),
+          const SizedBox(width: 8),
+          Expanded(
+            child: Text(
+              translate('shortcut-mobile-physical-keyboard-tip'),
+              style: TextStyle(color: theme.colorScheme.onSurface),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}

flutter/lib/mobile/pages/remote_page.dart

@@ -21,6 +21,7 @@ import '../../common/widgets/remote_input.dart';
 import '../../models/input_model.dart';
 import '../../models/model.dart';
 import '../../models/platform_model.dart';
+import '../../models/shortcut_model.dart';
 import '../../utils/image.dart';
 import '../widgets/dialog.dart';
 import '../widgets/custom_scale_widget.dart';
@@ -119,6 +120,18 @@ class _RemotePageState extends State<RemotePage> with WidgetsBindingObserver {
       }
       _disableAndroidSoftKeyboard(
           isKeyboardVisible: keyboardVisibilityController.isVisible);
+      // Seed shortcut action callbacks once the session is ready, so that
+      // global keyboard shortcuts work even if the user never opens the
+      // toolbar menu. The returned list is intentionally discarded — the
+      // side effect of registering callbacks (inside toolbarControls) is
+      // what we want here.
+      if (mounted) {
+        toolbarControls(context, widget.id, gFFI);
+        // Mobile has no DesktopTabController, so tab-switch shortcuts
+        // remain unregistered (they will simply log a no-handler debug
+        // line if a mobile user binds one — they have no tabs to switch).
+        registerSessionShortcutActions(gFFI);
+      }
     });
     WidgetsBinding.instance.addObserver(this);
   }

flutter/lib/mobile/pages/settings_page.dart

@@ -17,8 +17,10 @@ import '../../common/widgets/login.dart';
 import '../../consts.dart';
 import '../../models/model.dart';
 import '../../models/platform_model.dart';
+import '../../models/shortcut_model.dart';
 import '../widgets/dialog.dart';
 import 'home_page.dart';
+import 'mobile_keyboard_shortcuts_page.dart';
 import 'scan_page.dart';
 
 class SettingsPage extends StatefulWidget implements PageShape {
@@ -819,6 +821,22 @@ class _SettingsState extends State<SettingsPage> with WidgetsBindingObserver {
               showThemeSettings(gFFI.dialogManager);
             },
           ),
+          SettingsTile.navigation(
+            leading: Icon(Icons.keyboard_outlined),
+            title: Text(translate('Keyboard Shortcuts')),
+            description: Text(ShortcutModel.isEnabled()
+                ? translate('On')
+                : translate('Off')),
+            onPressed: (context) {
+              Navigator.push(
+                  context,
+                  MaterialPageRoute(
+                    builder: (_) => const MobileKeyboardShortcutsPage(),
+                  )).then((_) {
+                if (mounted) setState(() {});
+              });
+            },
+          ),
           if (!bind.isDisableAccount())
             SettingsTile.switchTile(
               title: Text(translate('note-at-conn-end-tip')),
@@ -1352,3 +1370,4 @@ SettingsTile _getPopupDialogRadioEntry({
     ),
   );
 }
+