fix(bot): Hub WS auto-approve Discord 알림 누락 + !auto 이중발송 dedup

bot.py

@@ -189,6 +189,7 @@ class GravityBot(commands.Bot):
         self.auto_approve_projects: set[str] = set()  # projects with auto-approve enabled
         self._processed_message_ids: deque[int] = deque(maxlen=200)  # dedup for Gateway event replay
         self._approval_messages: dict[str, int] = {}  # FIX #4: request_id → discord message_id (for auto_resolved lookup)
+        self._last_auto_toggle: dict[str, float] = {}  # project → timestamp (dedup for !auto embed)
         self.gateway = None  # Set by main.py in gateway mode
         self.hub = None       # Set by main.py in gateway mode (WSHub instance)
 
@@ -921,6 +922,14 @@ class GravityBot(commands.Bot):
 
         # Special command: !auto — toggle auto-approve
         if actual_text == "!auto":
+            # Dedup: skip if toggled within 5s for same project (Gateway event replay)
+            now = time.time()
+            last = self._last_auto_toggle.get(project, 0)
+            if now - last < 5.0:
+                logger.info(f"[AUTO] Dedup: skipping duplicate !auto for {project} ({now-last:.1f}s ago)")
+                return
+            self._last_auto_toggle[project] = now
+
             # Toggle per-project auto-approve
             if project in self.auto_approve_projects:
                 self.auto_approve_projects.discard(project)
@@ -1043,6 +1052,8 @@ class GravityBot(commands.Bot):
 
     async def _auto_approve_via_hub(self, request: ApprovalRequest):
         """Auto-approve a pending request via Hub."""
+        self._sent_approval_ids.add(request.request_id)
+
         if self.hub:
             await self.hub.send_response_to_pending_owner(request.request_id, {
                 "type": "response",
@@ -1060,7 +1071,20 @@ class GravityBot(commands.Bot):
             step_type=request.step_type,
             project_name=request.project_name,
         ))
-        logger.info(f"[HUB-AUTO] Auto-approved: {request.request_id[:12]}")
+        # Send compact auto-approved embed to Discord (was missing — caused silent approvals)
+        channel = await self._get_channel(request.project_name)
+        if channel:
+            try:
+                embed = discord.Embed(
+                    title="🤖 자동 승인됨",
+                    description=f"```\n{request.command[:500]}\n```",
+                    color=discord.Color.green(),
+                )
+                embed.set_footer(text=f"auto-approve | {request.request_id[:12]}")
+                await channel.send(embed=embed)
+            except Exception as e:
+                logger.error(f"[HUB-AUTO] Discord send failed: {e}")
+        logger.info(f"[HUB-AUTO] Auto-approved: {request.request_id[:12]} project={request.project_name}")
 
     async def _hub_on_chat(self, project: str, data: dict):
         """Handle chat snapshot from Hub (Extension->Hub->Bot->Discord)."""