fix(gamebook): always regenerate the PLIP menu WAV

The spoken story menu was cached by filename, so incremental deploys
(adding a story) kept announcing the old, shorter list. Force-rebuild
menu.wav each run since its content tracks the (cumulative) book list.

tools/gamebook/build_phone_gamebook.py

@@ -173,9 +173,12 @@ def main() -> int:
 
     fail = pushed = 0
 
-    # Menu WAV (the spoken story picker).
+    # Menu WAV (the spoken story picker). ALWAYS regenerated: its content
+    # depends on the (cumulative) book list, so a cached menu.wav would still
+    # announce an old, shorter set of stories.
     menu = OUT_DIR / "menu.wav"
-    if synth_wav(menu_narration(books_meta), menu, args.force, args.tts):
+    menu.unlink(missing_ok=True)
+    if synth_wav(menu_narration(books_meta), menu, True, args.tts):
         if not args.dry_run:
             ok, _ = push(args.ip, "menu.wav", menu.read_bytes()); pushed += ok; fail += not ok
     else: