fix: 채널 중복 완전 근절 - reconnect 시 이름 dedup + 자동 삭제 + project name 최소 5자

bot.py

@@ -81,12 +81,14 @@ class ApprovalView(discord.ui.View):
 
 def detect_project_name(conv_dir: Path) -> str:
     """Extract project name from conversation artifacts.
-    Output: lowercase_with_underscores (e.g. 'gravity_control')
+    Returns: lowercase_with_underscores (e.g. 'gravity_control')
+    Uses FIRST successful extraction and caches it.
     """
     short_id = conv_dir.name[:8]
 
     def _sanitize(raw: str) -> str:
-        for suffix in ["Task Tracker", "— Task Tracker", "태스크", "구현 계획"]:
+        for suffix in ["Task Tracker", "— Task Tracker", "태스크", "구현 계획",
+                        "Implementation Plan", "Walkthrough"]:
             raw = raw.replace(suffix, "")
         raw = raw.strip(" —-–")
         raw = re.sub(r'[^a-zA-Z0-9가-힣\s\-]', '', raw)
@@ -102,7 +104,8 @@ def detect_project_name(conv_dir: Path) -> str:
                     match = re.match(r'^#\s+(.+)', line)
                     if match:
                         name = _sanitize(match.group(1))
-                        if name and name != "task":
+                        # Require at least 5 chars to avoid short generic names
+                        if name and name != "task" and len(name) >= 5:
                             return name
             except (OSError, UnicodeDecodeError):
                 pass
@@ -161,20 +164,40 @@ class GravityBot(commands.Bot):
         await self._reconnect_existing_channels()
 
     async def _reconnect_existing_channels(self):
-        """Scan existing Discord channels and map them to conversation IDs."""
+        """Scan existing Discord channels and map them — MERGE same-name channels."""
         if not self.session_category:
             return
 
-        count = 0
+        # Group channels by normalized name
+        name_to_channel: dict[str, discord.TextChannel] = {}
+        duplicates: list[discord.TextChannel] = []
+
         for ch in self.session_category.text_channels:
             if ch.topic and "Antigravity Session:" in ch.topic:
-                conv_id = ch.topic.replace("Antigravity Session:", "").strip()
-                if conv_id:
-                    self.session_channels[conv_id] = ch
-                    await self._recover_task_message(ch, conv_id)
-                    count += 1
+                if ch.name in name_to_channel:
+                    # DUPLICATE — mark for cleanup
+                    duplicates.append(ch)
+                else:
+                    name_to_channel[ch.name] = ch
 
-        logger.info(f"Reconnected to {count} existing channels")
+        # Map the primary channel for each name
+        count = 0
+        for ch in name_to_channel.values():
+            conv_id = ch.topic.replace("Antigravity Session:", "").strip()
+            if conv_id:
+                self.session_channels[conv_id] = ch
+                await self._recover_task_message(ch, conv_id)
+                count += 1
+
+        # Delete duplicate channels
+        for ch in duplicates:
+            try:
+                await ch.delete(reason="Duplicate channel cleanup")
+                logger.info(f"Deleted duplicate channel: #{ch.name}")
+            except (discord.Forbidden, discord.HTTPException) as e:
+                logger.warning(f"Failed to delete duplicate #{ch.name}: {e}")
+
+        logger.info(f"Reconnected to {count} channels, cleaned {len(duplicates)} duplicates")
 
     async def _recover_task_message(
         self, channel: discord.TextChannel, conversation_id: str
@@ -196,21 +219,25 @@ class GravityBot(commands.Bot):
     async def _ensure_channel(
         self, conversation_id: str, project_name: str
     ) -> discord.TextChannel:
-        """Get or create a channel. Uses GLOBAL lock + OWN dict lookup (no cache issues)."""
-        # Fast path: already mapped
+        """Get or create a channel. SINGLE channel per project name, guaranteed."""
+        channel_name = f"{Config.CHANNEL_PREFIX}-{project_name}"
+        target_name = channel_name.lower().replace(" ", "-")
+
+        # Fast path: this conv_id already mapped
         if conversation_id in self.session_channels:
-            return self.session_channels[conversation_id]
+            ch = self.session_channels[conversation_id]
+            # Verify the channel name matches (project name might have changed)
+            if ch.name == target_name:
+                return ch
 
         async with self._channel_create_lock:
             # Double-check after lock
             if conversation_id in self.session_channels:
-                return self.session_channels[conversation_id]
+                ch = self.session_channels[conversation_id]
+                if ch.name == target_name:
+                    return ch
 
-            channel_name = f"{Config.CHANNEL_PREFIX}-{project_name}"
-            target_name = channel_name.lower().replace(" ", "-")
-
-            # Check OWN dict for a channel with the same NAME
-            # (different conv IDs can share one channel)
+            # Check ALL mapped channels for same name
             for cid, ch in self.session_channels.items():
                 if ch.name == target_name:
                     self.session_channels[conversation_id] = ch
@@ -218,7 +245,7 @@ class GravityBot(commands.Bot):
                     logger.info(f"Reusing channel #{ch.name} for {conversation_id[:8]}")
                     return ch
 
-            # Create new channel (truly first time)
+            # Create new channel (truly no match anywhere)
             try:
                 channel = await self.guild.create_text_channel(
                     name=channel_name,