Add Discord-native hybrid front-end for Jarvis (bot + bridge)

Transform isair/jarvis into a Discord-controlled voice assistant running on
the Ubuntu VNC desktop, keeping the mature ~39k-line Python brain intact.

- bot/ (Node + bun, discord.js): /자비스 slash commands (ephemeral),
  voice channel join + voice receive/playback, pluggable VNC screen broadcast
  (selfbot live / noVNC / screenshot)
- bridge/ (Python, Flask): wraps jarvis STT + run_reply_engine + Piper TTS
  behind a thin localhost HTTP API
- .env.example, scripts/ (start_bridge/start_bot/dev), README rewrite,
  docs/language-comparison.md and docs/vnc-xfce-setup.md

Language decision: hybrid (Python brain + Node/bun Discord layer) because
Discord blocks bot video; native screen broadcast only works via a Node
selfbot library.

scripts/run_desktop_app.bat

@@ -0,0 +1,84 @@
+@echo off
+REM Run script for the Jarvis Desktop App on Windows
+REM Uses the project's mamba environment
+REM Usage: run_desktop_app.bat [--voice-debug]
+
+REM Parse arguments
+set "VOICE_DEBUG=0"
+:parse_args
+if "%~1"=="" goto done_args
+if "%~1"=="--voice-debug" (
+    set "VOICE_DEBUG=1"
+    shift
+    goto parse_args
+)
+shift
+goto parse_args
+:done_args
+
+echo Testing Jarvis Desktop App locally...
+if "%VOICE_DEBUG%"=="1" (
+    echo    Voice debug: ENABLED
+)
+echo.
+
+REM Navigate to project root (use for-loop to resolve .. reliably across shells)
+for %%I in ("%~dp0..") do set "PROJECT_ROOT=%%~fI"
+cd /d "%PROJECT_ROOT%"
+set "PYTHONPATH=%PROJECT_ROOT%\src;%PYTHONPATH%"
+
+REM Resolve mamba env: prefer this checkout's own, fall back to the main
+REM repo's when running from a git worktree (worktrees share one env).
+set "MAMBA_ENV=%PROJECT_ROOT%\.mamba_env"
+if not exist "%MAMBA_ENV%\python.exe" call :resolve_mamba_from_worktree
+
+REM Check if mamba environment exists
+if not exist "%MAMBA_ENV%\python.exe" (
+    echo ERROR: Mamba environment not found.
+    echo    Looked in: %PROJECT_ROOT%\.mamba_env
+    echo    And the main repo's .mamba_env ^(if this is a git worktree^).
+    echo Please run the setup script first.
+    pause
+    exit /b 1
+)
+
+REM Check Python version in mamba env
+echo Checking Python version...
+"%MAMBA_ENV%\python.exe" --version
+echo.
+
+REM Install/update dependencies from requirements.txt
+echo Installing dependencies...
+"%MAMBA_ENV%\python.exe" -m pip install -q -r requirements.txt
+if errorlevel 1 (
+    echo WARNING: Some dependencies may have failed to install
+)
+echo.
+
+REM Generate icons
+echo Generating icons...
+"%MAMBA_ENV%\python.exe" src\desktop_app\desktop_assets\generate_icons.py
+echo.
+
+REM Run the desktop app
+echo Starting desktop app...
+echo    Click the system tray icon to open menu
+echo    Select 'Start Listening' from menu to begin
+echo    Or press Ctrl+C to quit
+echo.
+
+REM Set voice debug environment variable if requested
+if "%VOICE_DEBUG%"=="1" (
+    set "JARVIS_VOICE_DEBUG=1"
+)
+
+"%MAMBA_ENV%\python.exe" -m desktop_app
+goto :eof
+
+:resolve_mamba_from_worktree
+for /f "usebackq delims=" %%G in (`git -C "%PROJECT_ROOT%" rev-parse --git-common-dir 2^>nul`) do set "GIT_COMMON_DIR=%%G"
+if not defined GIT_COMMON_DIR goto :eof
+for %%I in ("%GIT_COMMON_DIR%\..") do set "MAIN_REPO=%%~fI"
+if exist "%MAIN_REPO%\.mamba_env\python.exe" set "MAMBA_ENV=%MAIN_REPO%\.mamba_env"
+goto :eof
+