align LRC from ready text.txt via stable-ts and auto-detect language

- add align_text_to_audio(): forced alignment without ASR, fast
- add _StableTSModels cache; detect language via stable-ts when language=None
- LRC stage: use existing text.txt, copy it if already LRC, fall back to ASR only
- filter junk lyrics from tags and ASR hallucinations (promo phrases, tics)
- mark empty ASR results with metadata.empty_text and skip them on resume
- warn in GUI when LRC is run with transcription disabled
- add mark_no_speech.py one-shot script for existing tracks

gui/main_window.py

@@ -728,6 +728,12 @@ class MainWindow(QMainWindow):
                 "Этап генерации LRC выключен. Включите его на вкладке LRC."
             )
             return
+        if task == "lrc" and not cfg.transcribe.enabled:
+            QMessageBox.information(
+                self, "Транскрибация выключена",
+                "Транскрибация отключена, ASR запускаться не будет."
+                "LRC будет построен только по готовым text.txt."
+            )
         if task == "embed" and not cfg.lrc.embed_enabled:
             QMessageBox.warning(
                 self, "Встраивание LRC отключено",