fix(text-cache): apply model version migration on existing dbs

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

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

@@ -8,6 +8,13 @@
       "when": 1780329073891,
       "tag": "0000_tricky_mysterio",
       "breakpoints": true
+    },
+    {
+      "idx": 1,
+      "version": "7",
+      "when": 1780329074000,
+      "tag": "0001_add_model_version_to_cache",
+      "breakpoints": true
     }
   ]
 }