feat(commands): add PC control packs — volume, apps, file_search, output_device

All four packs are pure Lua (sandbox=full) and call out to PowerShell helpers
where COM / native APIs are needed. No new Rust code, no rebuild required:
post_build.py --sync copies them under target/{debug,release}/resources/.

volume/
  - volume_up / volume_down: 5x VK_VOLUME_UP|DOWN via keybd_event
  - volume_mute: VK_VOLUME_MUTE
  - volume_max: 50x VK_VOLUME_UP (system clamps)
  Helper _volume_helper.ps1 P/Invokes user32!keybd_event.

apps/
  - open_browser  : start "" https://www.google.com (uses system default browser)
  - open_notepad  : notepad.exe
  - open_calculator: calc.exe
  - open_explorer : explorer.exe
  - open_terminal : wt.exe, falls back to powershell.exe
  - open_settings : ms-settings: protocol
  - open_task_manager: taskmgr.exe
  - lock_screen   : rundll32 user32.dll,LockWorkStation
  - screenshot    : System.Drawing capture to ~/Pictures/jarvis_screenshot_*.png

file_search/
  - find file <query> : recursive Get-ChildItem in Desktop/Documents/Downloads
    (depth 3, top 5 matches). Strips Russian/English/Ukrainian trigger
    prefixes from the recognized phrase, then opens explorer /select on the
    first hit and notifies with the total count.

output_device/
  - list_output_devices : enumerates active render endpoints via
    IMMDeviceEnumerator and notifies friendly names with indices
  - next_output_device  : cycles the system default render device via the
    undocumented IPolicyConfig::SetDefaultEndpoint (eConsole/Multimedia/
    Communications). Tested locally — listed 7 devices, current correctly
    identified at index 5.

resources/commands/output_device/command.toml

@@ -0,0 +1,55 @@
+[[commands]]
+id = "list_output_devices"
+type = "lua"
+script = "list_devices.lua"
+sandbox = "full"
+timeout = 8000
+
+[commands.phrases]
+ru = [
+    "какие устройства вывода",
+    "покажи устройства",
+    "список устройств",
+    "какие наушники",
+    "какие колонки",
+]
+en = [
+    "list output devices",
+    "show audio devices",
+    "list speakers",
+    "what audio devices",
+]
+ua = [
+    "які пристрої виводу",
+    "покажи пристрої",
+    "список пристроїв",
+]
+
+
+[[commands]]
+id = "next_output_device"
+type = "lua"
+script = "next_device.lua"
+sandbox = "full"
+timeout = 8000
+
+[commands.phrases]
+ru = [
+    "переключи устройство",
+    "переключи звук",
+    "следующее устройство",
+    "смени вывод",
+    "переключи на наушники",
+    "переключи на колонки",
+]
+en = [
+    "switch audio device",
+    "next audio device",
+    "switch output",
+    "switch speakers",
+]
+ua = [
+    "перемкни пристрій",
+    "перемкни звук",
+    "наступний пристрій",
+]