drop the hive's push of the legacy core/meta repo

Nothing reads core/meta: builds come from internal/meta. Remove push_meta, ensure_meta_remote, meta_read_access, ensure_repo, the per-agent forge sync that only served them, and the git commit path in meta.rs; remove_permission_files now just deletes the seed files.

frontend/packages/dashboard/src/tabs.js

@@ -172,7 +172,7 @@ import { renderUserMenu } from "./user-menu.js";
       // broker traffic flows through the SSE channel. The only
       // /api/state fetches are the initial cold load and the
       // post-submit refetch on forms without `data-no-refresh`
-      // (tombstones, meta-input updates).
+      // (tombstones).
       if (pollTimer) {
         clearTimeout(pollTimer);
         pollTimer = null;