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

README.md

@@ -525,4 +525,4 @@ We officially thank the following contributors for their help in making this rep
 
 ## Star History
 
-[![Star History Chart](https://api.star-history.com/svg?repos=sickn33/antigravity-awesome-skills&type=date&legend=top-left)](https://www.star-history.com/#sickn33/antigravity-awesome-skills&type=date&legend=top-left)
+[![Star History Chart](assets/star-history.svg)](https://www.star-history.com/#sickn33/antigravity-awesome-skills&type=date&legend=top-left)

assets/star-history.svg

@@ -0,0 +1,9 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="800" height="400" viewBox="0 0 800 400">
+  <rect width="800" height="400" fill="#0b0f14" />
+  <text x="40" y="120" fill="#e6edf3" font-family="ui-sans-serif, system-ui, -apple-system" font-size="28">
+    Star History chart will be generated by CI.
+  </text>
+  <text x="40" y="170" fill="#9da7b3" font-family="ui-sans-serif, system-ui, -apple-system" font-size="18">
+    Run the Update Star History Chart workflow to refresh.
+  </text>
+</svg>