feat: parity with rust fork — LLM auto-fallback + 6 new action types + 20+ commands

Brings the python fork in line with the new feature/pc-tools work that
landed in rust. Same UX, same trigger phrases, same env vars.

config.py:
  + LLM_AUTO_FALLBACK = True
  + LLM_AUTO_FALLBACK_MIN_CHARS = 4
    Mirrors the rust config knobs. The old "скажи X" trigger still works
    (VA_TBR strips it before intent matching, so what remains hits this
    fallback anyway) — but now ANY unrecognized query goes to Groq, not
    just "скажи" ones.

main.py:
  va_respond: replaced the fuzz-on-"скажи" gate with a unified auto-
  fallback that fires whenever no command matches, GROQ_TOKEN is set,
  and the utterance is at least LLM_AUTO_FALLBACK_MIN_CHARS long.

  + _speak(text): recorder.stop() → tts.va_speak → start, used by the
    new action handlers so the mic doesn't pick up the assistant.
  + _set_clipboard(text): subprocess to PowerShell Set-Clipboard, no
    new python deps.
  + _strip_trigger(voice, triggers): shared helper for codegen/file_search
    where we need the text AFTER the trigger phrase.

  New action handlers (registered in run_action dispatch):
  + groq_codegen — extracts query, calls Groq with strict "code only"
    system prompt at temp 0.2, strips ```lang ... ``` fences, puts the
    result in the clipboard, speaks "Код в буфере, сэр. Строк: N".
  + ocr_screen — PowerShell System.Drawing screenshot to a temp PNG,
    shells to tesseract.exe (-l rus+eng), speaks a 120-char preview,
    clipboard. Looks for tesseract on PATH first then standard install
    dirs; gives a clear "Tesseract не установлен" if missing.
  + sysinfo — CIM-based battery/cpu/ram/disk via PS one-liners, time
    via python datetime (gets us localized weekday for free). Topics:
    time / battery / cpu / ram / disk / all.
  + file_search — strips trigger, recursive Get-ChildItem in Desktop/
    Documents/Downloads (depth 3, top 5), opens explorer /select on
    the first hit, speaks count and basename.
  + audio_devices_panel — opens mmsys.cpl. Proper COM-based device
    switching (like the rust IPolicyConfig version) is deferred — TODO
    in backlog.

commands.yaml:
  Total 33 commands (was 19). New:
  + open_notepad / open_calculator / open_explorer / open_terminal
    / open_settings / open_task_manager / lock_screen / screenshot
    — all via shell action (no AHK exes needed).
  + volume_up / volume_down — five chained keys=volumeup/volumedown
    presses each, like rust's _volume_helper.ps1 with Times=5.
  + media_stop — keys=stop.
  + sysinfo_time / sysinfo_battery / sysinfo_cpu / sysinfo_ram /
    sysinfo_disk / sysinfo_all — sysinfo action.
  + file_search, codegen, read_screen, switch_audio_device.

  Replaced (were AHK exes that Priler ships and we don't have):
  ~ music → keys playpause
  ~ music_off → keys playpause (toggle)
  ~ music_next → keys nexttrack
  ~ music_prev → keys prevtrack

  Removed (Priler hardware/setup specific, can't sensibly port):
  - gaming_mode_on / gaming_mode_off (display config switch)
  - music_save (depends on the specific player AHK was driving)
  - switch_to_headphones / switch_to_dynamics (replaced with the
    generic switch_audio_device that opens mmsys.cpl)

  Kept as-is (worked already, no AHK dependency):
  open_browser / open_youtube / open_google (url action)
  sound_off / sound_on (pycaw via system.volume_mute/unmute)
  thanks / stupid / off

Smoke-tested: yaml.safe_load → 33 commands, ast.parse main.py → OK.

Portability: USERPROFILE for screenshot path, $env:SystemDrive for disk,
PATH lookup for tesseract before falling back to standard install dirs.
No hardcoded user-specific paths.

config.py

@@ -31,6 +31,12 @@ GROQ_TOKEN = os.getenv('GROQ_TOKEN')
 GROQ_BASE_URL = "https://api.groq.com/openai/v1"
 GROQ_MODEL = "llama-3.3-70b-versatile"
 
+# LLM auto-fallback: route unrecognized commands straight to Groq instead of
+# playing the "not_found" sound. The old "скажи X" trigger still works (TBR
+# strips it before intent matching, so what remains hits this fallback anyway).
+LLM_AUTO_FALLBACK = True
+LLM_AUTO_FALLBACK_MIN_CHARS = 4
+
 # VAD (webrtcvad) — определяет конец команды по тишине вместо фиксированных 10 сек.
 # 0..3, выше — агрессивнее режет шум (но и обрезает речь).
 VAD_AGGRESSIVENESS = 2