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.

src/jarvis/memory/embeddings.py

@@ -0,0 +1,19 @@
+from __future__ import annotations
+import requests
+
+
+def get_embedding(text: str, base_url: str, model: str, timeout_sec: float = 15.0) -> list[float] | None:
+    try:
+        resp = requests.post(
+            f"{base_url.rstrip('/')}/api/embeddings",
+            json={"model": model, "prompt": text},
+            timeout=timeout_sec,
+        )
+        resp.raise_for_status()
+        data = resp.json()
+        vec = data.get("embedding")
+        if isinstance(vec, list):
+            return [float(x) for x in vec]
+    except Exception:
+        return None
+    return None