chore(db): add migration dropping position from asset_usages unique key

Generated migration for the narrowed
asset_usages_asset_target_slot_unique constraint (asset_id, target_type,
target_id, slot_type, slot_key). Run the duplicate cleanup before
applying — existing rows that differ only by position will otherwise
violate the new constraint.

packages/db/src/migrations/0001_slow_lila_cheney.sql

@@ -0,0 +1,2 @@
+ALTER TABLE "asset_usages" DROP CONSTRAINT "asset_usages_asset_target_slot_unique";--> statement-breakpoint
+ALTER TABLE "asset_usages" ADD CONSTRAINT "asset_usages_asset_target_slot_unique" UNIQUE("asset_id","target_type","target_id","slot_type","slot_key");

packages/db/src/migrations/meta/_journal.json

@@ -8,6 +8,13 @@
       "when": 1781617442553,
       "tag": "0000_shocking_carmella_unuscione",
       "breakpoints": true
+    },
+    {
+      "idx": 1,
+      "version": "7",
+      "when": 1782684436805,
+      "tag": "0001_slow_lila_cheney",
+      "breakpoints": true
     }
   ]
-}
+}