Add shortcuts hint and panel for discoverability (#18035)

packages/cli/src/ui/AppContainer.tsx

@@ -760,6 +760,7 @@ Logging in with Google... Restarting Gemini CLI to continue.
   const setIsBackgroundShellListOpenRef = useRef<(open: boolean) => void>(
     () => {},
   );
+  const [shortcutsHelpVisible, setShortcutsHelpVisible] = useState(false);
 
   const slashCommandActions = useMemo(
     () => ({
@@ -795,6 +796,7 @@ Logging in with Google... Restarting Gemini CLI to continue.
           }
         }
       },
+      toggleShortcutsHelp: () => setShortcutsHelpVisible((visible) => !visible),
       setText: stableSetText,
     }),
     [
@@ -813,6 +815,7 @@ Logging in with Google... Restarting Gemini CLI to continue.
       openPermissionsDialog,
       addConfirmUpdateExtensionRequest,
       toggleDebugProfiler,
+      setShortcutsHelpVisible,
       stableSetText,
     ],
   );
@@ -1840,6 +1843,7 @@ Logging in with Google... Restarting Gemini CLI to continue.
       ctrlCPressedOnce: ctrlCPressCount >= 1,
       ctrlDPressedOnce: ctrlDPressCount >= 1,
       showEscapePrompt,
+      shortcutsHelpVisible,
       isFocused,
       elapsedTime,
       currentLoadingPhrase,
@@ -1945,6 +1949,7 @@ Logging in with Google... Restarting Gemini CLI to continue.
       ctrlCPressCount,
       ctrlDPressCount,
       showEscapePrompt,
+      shortcutsHelpVisible,
       isFocused,
       elapsedTime,
       currentLoadingPhrase,
@@ -2044,6 +2049,7 @@ Logging in with Google... Restarting Gemini CLI to continue.
       handleApiKeySubmit,
       handleApiKeyCancel,
       setBannerVisible,
+      setShortcutsHelpVisible,
       handleWarning,
       setEmbeddedShellFocused,
       dismissBackgroundShell,
@@ -2120,6 +2126,7 @@ Logging in with Google... Restarting Gemini CLI to continue.
       handleApiKeySubmit,
       handleApiKeyCancel,
       setBannerVisible,
+      setShortcutsHelpVisible,
       handleWarning,
       setEmbeddedShellFocused,
       dismissBackgroundShell,