feat: session connect command + auto-registration + bridge/register protocol

bot.py

@@ -140,12 +140,38 @@ class GravityBot(commands.Bot):
         # Discover existing project channels
         await self._discover_channels()
 
+        # Load conversation → project registrations from Extension
+        self._load_registrations()
+
         # Open the gate
         self._ready_event.set()
         logger.info("Ready gate opened — event processing enabled")
 
     # ─── Channel Management ──────────────────────────────────────────
 
+    def _load_registrations(self):
+        """Read bridge/register/ to learn conversation → project mappings."""
+        register_dir = self.bridge.bridge_dir / "register"
+        if not register_dir.exists():
+            return
+
+        count = 0
+        for f in register_dir.glob("*.json"):
+            try:
+                data = json.loads(f.read_text(encoding="utf-8-sig"))
+                conv_id = data.get("conversation_id", "")
+                project = data.get("project_name", "")
+                if conv_id and project:
+                    self.conv_to_project[conv_id] = project
+                    count += 1
+            except (json.JSONDecodeError, OSError):
+                pass
+
+        if count:
+            logger.info(f"Loaded {count} conversation→project registrations")
+
+    # ─── Channel Management ──────────────────────────────────────────
+
     async def _discover_channels(self):
         """Find existing project channels via Discord API (not cache)."""
         all_channels = await self.guild.fetch_channels()