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/launch.py

@@ -0,0 +1,56 @@
+"""Cross-platform launcher for Claude Code preview_start.
+
+Detects the OS and delegates to the appropriate platform-specific script
+(bat on Windows, sh on macOS/Linux). Can be invoked with any Python 3.x.
+
+Usage:
+    python scripts/launch.py <script_name> [args...]
+
+Examples:
+    python scripts/launch.py run_desktop_app
+    python scripts/launch.py run_desktop_app --voice-debug
+    python scripts/launch.py run_evals
+"""
+
+import os
+import platform
+import subprocess
+import sys
+
+
+def main():
+    if len(sys.argv) < 2:
+        print("Usage: python scripts/launch.py <script_name> [args...]")
+        sys.exit(1)
+
+    script_name = sys.argv[1]
+    extra_args = sys.argv[2:]
+
+    project_root = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+    scripts_dir = os.path.join(project_root, "scripts")
+
+    if platform.system() == "Windows":
+        script_path = os.path.join(scripts_dir, f"{script_name}.bat")
+        if not os.path.isfile(script_path):
+            print(f"ERROR: {script_path} not found")
+            sys.exit(1)
+        result = subprocess.run(
+            [script_path] + extra_args,
+            cwd=project_root,
+            shell=True,
+        )
+    else:
+        script_path = os.path.join(scripts_dir, f"{script_name}.sh")
+        if not os.path.isfile(script_path):
+            print(f"ERROR: {script_path} not found")
+            sys.exit(1)
+        result = subprocess.run(
+            ["bash", script_path] + extra_args,
+            cwd=project_root,
+        )
+
+    sys.exit(result.returncode)
+
+
+if __name__ == "__main__":
+    main()