feat(db): add migration to drop unused AI columns and dynamically resolve initial migration tag

services/discord-gateway/drizzle/migrations/0004_drop_unused_ai_columns.sql

@@ -0,0 +1,7 @@
+-- Migration: 0004_drop_unused_ai_columns
+-- Converts orphaned raw SQL from src/shared/database/migrations/001_drop_unused_ai_columns.sql
+-- These column definitions were removed from the Drizzle schema but old databases
+-- created before the refactor still have them. Drizzle never ran the raw SQL.
+ALTER TABLE messages DROP COLUMN IF EXISTS ai_moderation_raw;
+ALTER TABLE messages DROP COLUMN IF EXISTS ai_policy_version;
+ALTER TABLE messages DROP COLUMN IF EXISTS ai_evidence;

services/discord-gateway/drizzle/migrations/meta/_journal.json

@@ -29,6 +29,13 @@
       "when": 1780418603164,
       "tag": "0003_add_corrected_moderations",
       "breakpoints": true
+    },
+    {
+      "idx": 4,
+      "version": "7",
+      "when": 1780418800000,
+      "tag": "0004_drop_unused_ai_columns",
+      "breakpoints": true
     }
   ]
 }