migration: Drop orphaned approval columns from initiatives and tasks

merge_requires_approval (initiatives) and requires_approval (tasks)
were removed from schema.ts in the task-approval removal but left in
the DB because 0030 assumed SQLite couldn't DROP COLUMN. SQLite 3.35+
supports it. These orphaned columns caused the old stale-build approval
code path to silently set detail tasks to pending_approval, stranding
them and blocking phase completion.

apps/server/drizzle/meta/_journal.json

@@ -232,6 +232,13 @@
       "when": 1772323200000,
       "tag": "0032_add_comment_threading",
       "breakpoints": true
+    },
+    {
+      "idx": 33,
+      "version": "6",
+      "when": 1772409600000,
+      "tag": "0033_drop_approval_columns",
+      "breakpoints": true
     }
   ]
 }