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.

tests/test_recall_gate.py

@@ -0,0 +1,75 @@
+"""Tests for recall_gate.should_recall — cheap heuristic for skipping
+long-term memory enrichment when the hot-window already covers the topic.
+"""
+
+import pytest
+
+from src.jarvis.memory.recall_gate import should_recall
+
+
+@pytest.mark.unit
+class TestShouldRecall:
+    def test_empty_hot_window_always_recalls(self):
+        assert should_recall("who is justin bieber", []) is True
+
+    def test_no_tool_result_in_history_always_recalls(self):
+        recent = [
+            {"role": "user", "content": "who is justin bieber"},
+            {"role": "assistant", "content": "He is a Canadian singer."},
+        ]
+        # No tool row → no fresh grounded data → recall (diary may know more)
+        assert should_recall("what is his most famous song", recent) is True
+
+    def test_tool_covered_topic_skips_recall(self):
+        recent = [
+            {"role": "user", "content": "who is justin bieber"},
+            {"role": "assistant", "content": "", "tool_calls": [
+                {"id": "c1", "type": "function",
+                 "function": {"name": "webSearch",
+                              "arguments": {"query": "justin bieber"}}}
+            ]},
+            {"role": "tool", "tool_call_id": "c1",
+             "content": "Justin Bieber is a Canadian singer with hits like Baby."},
+            {"role": "assistant", "content": "Canadian singer."},
+        ]
+        # Follow-up on same entity, fresh tool row present → skip
+        assert should_recall("what is his most famous song bieber hits",
+                             recent) is False
+
+    def test_topic_change_still_recalls(self):
+        recent = [
+            {"role": "user", "content": "who is justin bieber"},
+            {"role": "tool", "tool_call_id": "c1",
+             "content": "Justin Bieber is a Canadian singer."},
+            {"role": "assistant", "content": "Canadian singer."},
+        ]
+        # Completely different topic → no overlap → recall runs
+        assert should_recall("what's the weather in hackney", recent) is True
+
+    def test_non_latin_script_query_matches_hot_window(self):
+        """Per CLAUDE.md the gate must be language-agnostic. A Cyrillic query
+        covered by a Cyrillic tool result should skip recall just like English.
+        """
+        recent = [
+            {"role": "user", "content": "кто такой пушкин"},
+            {"role": "tool", "tool_call_id": "c1",
+             "content": "Пушкин это русский поэт девятнадцатого века."},
+            {"role": "assistant", "content": "Русский поэт."},
+        ]
+        assert should_recall("пушкин русский поэт стихи", recent) is False
+
+    def test_non_latin_topic_change_still_recalls(self):
+        recent = [
+            {"role": "user", "content": "кто такой пушкин"},
+            {"role": "tool", "tool_call_id": "c1",
+             "content": "Пушкин это русский поэт."},
+        ]
+        # Different topic in the same script → no overlap → recall
+        assert should_recall("какая сегодня погода", recent) is True
+
+    def test_stopword_only_query_does_not_skip(self):
+        recent = [
+            {"role": "tool", "tool_call_id": "c1", "content": "foo bar"},
+        ]
+        # "what is it" has no content words → cannot justify skipping
+        assert should_recall("what is it", recent) is True