chore: auto-update star history chart

Add a scheduled workflow that refreshes assets/star-history.svg daily and updates README to reference the local asset.

.github/workflows/star-history.yml

@@ -0,0 +1,38 @@
+name: Update Star History Chart
+
+on:
+  workflow_dispatch:
+  schedule:
+    # Daily at 06:00 UTC
+    - cron: "0 6 * * *"
+
+permissions:
+  contents: write
+
+jobs:
+  update-star-history:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Fetch latest chart (SVG)
+        run: |
+          set -euo pipefail
+          mkdir -p assets
+          curl -fsSL \
+            "https://api.star-history.com/svg?repos=sickn33/antigravity-awesome-skills&type=date&legend=top-left" \
+            -o assets/star-history.svg
+
+      - name: Commit and push if changed
+        run: |
+          set -euo pipefail
+          if git diff --quiet; then
+            echo "No changes in star-history.svg"
+            exit 0
+          fi
+
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+          git add assets/star-history.svg
+          git commit -m "chore: update star history chart"
+          git push