ci: add repomix workflow to pack repo as artifact

Author: bug3

.github/workflows/repomix.yml

@@ -0,0 +1,23 @@
+name: Repomix
+
+on:
+  push:
+    branches: [master]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  pack:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+      - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
+        with:
+          node-version: 22
+      - run: npx -y repomix
+      - uses: actions/upload-artifact@v4
+        with:
+          name: repomix-output
+          path: repomix-output.xml