Disable topic drift monitoring in general channel

Add ignored_channels config to topic_drift section, supporting
channel names or IDs. General channel excluded from off-topic
warnings while still receiving full moderation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cogs/sentiment.py

@@ -430,6 +430,11 @@ class SentimentCog(commands.Cog):
         if not config.get("enabled", True):
             return
 
+        # Skip channels excluded from topic drift monitoring
+        ignored = config.get("ignored_channels", [])
+        if message.channel.id in ignored or getattr(message.channel, "name", "") in ignored:
+            return
+
         # Check if we're in dry-run mode — still track but don't act
         dry_run = self.bot.config.get("monitoring", {}).get("dry_run", False)
         if dry_run: