ci: re-enable nix hash workflow; add manual trigger

Author: NotAShelf

.github/workflows/nix-fix.yml

@@ -1,10 +1,11 @@
 name: Fix PNPM Dependency Hash
 
-# on:
-#   push:
-#     branches: [main]
-#   pull_request:
-#     branches: [main]
+on:
+  workflow_dispatch:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
 
 concurrency:
   group: ${{ github.workflow }}-$${{ github.head_ref || github.run_id }}