feat: US-009 - Autocomplete voci din catalog pentru /audio și /voice setvoice

- tools/tts.py: +list_voice_names(engine=None), sursă live din tts_voices.json
- src/fast_commands.py: _VOICES statice -> _supertonic_voice_names() din catalog
- discord_bot.py /audio și discord_voice.py /voice setvoice: choices statice -> autocomplete live
- gates rulate: tests PASS (1043 passed, 22 eșecuri preexistente neschimbate), ui/backend review PASS manual

src/fast_commands.py

@@ -712,11 +712,23 @@ Session:
 # Audio / TTS
 # ---------------------------------------------------------------------------
 
-_VOICES = {"M1", "M2", "M3", "M4", "M5", "F1", "F2", "F3", "F4", "F5"}
 _AUDIO_PREFIX = "__AUDIO__:"
 _MAX_TTS_CHARS = 3000
 
 
+def _supertonic_voice_names() -> set[str]:
+    """Nume de voci Supertonic din tts_voices.json (import lazy din tools/tts.py)."""
+    import sys as _sys
+    _tools_dir = str(TOOLS_DIR)
+    if _tools_dir not in _sys.path:
+        _sys.path.insert(0, _tools_dir)
+    try:
+        import tts as _tts_mod
+        return set(_tts_mod.list_voice_names(engine="supertonic"))
+    except Exception:
+        return {"M1", "M2", "M3", "M4", "M5", "F1", "F2", "F3", "F4", "F5"}
+
+
 def cmd_audio(args: list[str]) -> str:
     """TTS via Supertonic. Returnează __AUDIO__:/cale sau text de eroare.
 
@@ -732,7 +744,7 @@ def cmd_audio(args: list[str]) -> str:
     remaining = list(args)
 
     # Detectare voce ca prim token
-    if remaining and remaining[0].upper() in _VOICES:
+    if remaining and remaining[0].upper() in _supertonic_voice_names():
         voice = remaining[0].upper()
         remaining = remaining[1:]