fix: replace emoji characters with ASCII-safe markers for Windows compatibility

- Replace Unicode emoji (✓, ⚠️) with [OK] and [WARN] in audio_preprocessor.py
  to prevent UnicodeEncodeError on Windows console (cp1252 codec)
- Add auto-update dependencies function to bot.py for easier maintenance
- Remove setup_linux.sh (no longer needed)
- Update .gitignore to exclude VS Code launch.json

.gitignore

@@ -124,4 +124,5 @@ venv.bak/
 .numba_cache/
 # Gemini files
 GEMINI.md
-PROGRESS.md
+PROGRESS.md
+.vscode/launch.json