fix: asyncio.Lock on channel create + PROJECT_NAME in .env.example

.env.example

@@ -10,5 +10,8 @@ BRAIN_PATH=C:\Users\Certes\.gemini\antigravity\brain
 # 세션 활성 판단: 마지막 파일 변경으로부터 이 시간(초) 이내면 활성
 ACTIVE_TIMEOUT_SECONDS=300
 
+# Project name (used for Discord channel: AG-{PROJECT_NAME})
+PROJECT_NAME=gravity_control
+
 # Watcher Settings
 DEBOUNCE_SECONDS=2

bot.py

@@ -97,6 +97,7 @@ class GravityBot(commands.Bot):
         self.session_status_messages: dict[str, int] = {}  # conv_id → msg_id
         self._sent_approval_ids: set[str] = set()
         self._ready_event = asyncio.Event()
+        self._channel_lock = asyncio.Lock()  # Prevents double-create race
         self.bridge = BridgeProtocol()
         self.session_category: discord.CategoryChannel | None = None
         self.guild: discord.Guild | None = None
@@ -187,33 +188,38 @@ class GravityBot(commands.Bot):
     async def _get_project_channel(self) -> discord.TextChannel:
         """Get the project channel. Create if it doesn't exist yet.
 
-        Thread-safe: only ONE channel will ever be created because
-        self.project_channel acts as a singleton guard.
+        Uses asyncio.Lock to prevent race between event processor
+        and approval scanner both creating channels simultaneously.
         """
         if self.project_channel:
             return self.project_channel
 
-        # Create the channel
-        try:
-            self.project_channel = await self.guild.create_text_channel(
-                name=self._channel_name,
-                category=self.session_category,
-                topic=f"Gravity Control — Antigravity Bridge",
-            )
-            logger.info(f"Created project channel: #{self._channel_name}")
+        async with self._channel_lock:
+            # Double-check after acquiring lock
+            if self.project_channel:
+                return self.project_channel
 
-            embed = discord.Embed(
-                title=f"🚀 {Config.PROJECT_NAME}",
-                description=(
-                    f"Antigravity Bridge 연결됨\n"
-                    f"모든 세션 이벤트가 이 채널로 전달됩니다."
-                ),
-                color=discord.Color.blue(),
-                timestamp=datetime.now(timezone.utc),
-            )
-            await self.project_channel.send(embed=embed)
-        except discord.errors.Forbidden:
-            logger.error(f"No permission to create channel: {self._channel_name}")
+            # Create the channel
+            try:
+                self.project_channel = await self.guild.create_text_channel(
+                    name=self._channel_name,
+                    category=self.session_category,
+                    topic=f"Gravity Control — Antigravity Bridge",
+                )
+                logger.info(f"Created project channel: #{self._channel_name}")
+
+                embed = discord.Embed(
+                    title=f"🚀 {Config.PROJECT_NAME}",
+                    description=(
+                        f"Antigravity Bridge 연결됨\n"
+                        f"모든 세션 이벤트가 이 채널로 전달됩니다."
+                    ),
+                    color=discord.Color.blue(),
+                    timestamp=datetime.now(timezone.utc),
+                )
+                await self.project_channel.send(embed=embed)
+            except discord.errors.Forbidden:
+                logger.error(f"No permission to create channel: {self._channel_name}")
 
         return self.project_channel