Add single-escape navigation: back from signup/lobby, leave room

- Single Esc: goes back one step (signup→login, lobby→connect, room→lobby)
- Double Esc: still quits the app
- Footer bar shows [Esc] Back and [Esc][Esc] Quit hints on all screens

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

tui_client/src/tui_client/app.py

@@ -75,12 +75,16 @@ class GolfApp(App):
             handler(msg)
 
     def action_esc_pressed(self) -> None:
-        """Double-escape to hard quit. Single escape does nothing."""
+        """Single escape goes back, double-escape quits."""
         now = time.monotonic()
         if now - self._last_escape < 0.5:
             self.exit()
         else:
             self._last_escape = now
+            # Let the active screen handle single escape
+            handler = getattr(self.screen, "handle_escape", None)
+            if handler:
+                handler()
 
     def _update_keymap(self) -> None:
         """Update the keymap bar based on current screen."""
@@ -89,11 +93,11 @@ class GolfApp(App):
         if keymap:
             text = keymap
         elif screen_name == "ConnectScreen":
-            text = "[Tab] Navigate  [Enter] Submit  [Esc Esc] Quit"
+            text = "[Tab] Navigate  [Enter] Submit  [Esc][Esc] Quit"
         elif screen_name == "LobbyScreen":
-            text = "[Tab] Navigate  [Enter] Submit  [Esc Esc] Quit"
+            text = "[Esc] Back  [Tab] Navigate  [Enter] Submit  [Esc][Esc] Quit"
         else:
-            text = "[Esc Esc] Quit"
+            text = "[Esc][Esc] Quit"
         try:
             self.query_one("#keymap-bar", KeymapBar).update(text)
         except Exception:
@@ -104,8 +108,8 @@ class GolfApp(App):
 
         Always appends [Esc Esc] Quit on the right for discoverability.
         """
-        if "[Esc Esc]" not in text:
-            text = f"{text}  [Esc Esc] Quit"
+        if "[Esc]" not in text.replace("[Esc][Esc]", ""):
+            text = f"{text}  [Esc][Esc] Quit"
         try:
             self.query_one("#keymap-bar", KeymapBar).update(text)
         except Exception:

tui_client/src/tui_client/screens/connect.py

@@ -85,7 +85,7 @@ class ConnectScreen(Screen):
             self._set_status("")
             self._update_form_visibility()
 
-    def key_escape(self) -> None:
+    def handle_escape(self) -> None:
         """Escape goes back to login if on signup form."""
         if self._mode == "signup":
             self._mode = "login"

tui_client/src/tui_client/screens/lobby.py

@@ -231,14 +231,22 @@ class LobbyScreen(Screen):
     def _update_keymap(self) -> None:
         try:
             if self._in_room and self._is_host:
-                self.app.set_keymap("[+] Add CPU  [−] Remove CPU  [Enter] Start Game  [Esc Esc] Quit")
+                self.app.set_keymap("[Esc] Leave  [+] Add CPU  [−] Remove  [Enter] Start  [Esc][Esc] Quit")
             elif self._in_room:
-                self.app.set_keymap("Waiting for host to start...  [Esc Esc] Quit")
+                self.app.set_keymap("[Esc] Leave  Waiting for host...  [Esc][Esc] Quit")
             else:
-                self.app.set_keymap("[Tab] Navigate  [Enter] Create/Join  [Esc Esc] Quit")
+                self.app.set_keymap("[Esc] Back  [Tab] Navigate  [Enter] Create/Join  [Esc][Esc] Quit")
         except Exception:
             pass
 
+    def handle_escape(self) -> None:
+        """Single escape: leave room → pre-room, or pre-room → back to connect."""
+        if self._in_room:
+            self.run_worker(self._send("leave_game"))
+            self.reset_to_pre_room()
+        else:
+            self.app.pop_screen()
+
     def on_button_pressed(self, event: Button.Pressed) -> None:
         if event.button.id == "btn-create":
             self._create_room()