Add date to "No Contributions" tooltip (#36190)

Fixes https://github.com/go-gitea/gitea/issues/36188 via
52bbfd7a15.

Before:

<img width="183" height="92" alt="Screenshot 2025-12-18 at 16 50 18"
src="https://github.com/user-attachments/assets/f06ca7d6-a141-499f-b6da-e46064a44846"
/>

After:

<img width="292" height="78" alt="Screenshot 2025-12-18 at 17 08 36"
src="https://github.com/user-attachments/assets/b80f7391-7960-44ad-8184-ffab4c9a4ea7"
/>

If there will be more changes in the future, we should vendor this
module.

Co-authored-by: Giteabot <teabot@gitea.io>

package.json

@@ -17,7 +17,7 @@
     "@mcaptcha/vanilla-glue": "0.1.0-alpha-3",
     "@primer/octicons": "19.21.1",
     "@resvg/resvg-wasm": "2.6.2",
-    "@silverwind/vue3-calendar-heatmap": "2.0.6",
+    "@silverwind/vue3-calendar-heatmap": "2.1.1",
     "@techknowlogick/license-checker-webpack-plugin": "0.3.0",
     "add-asset-webpack-plugin": "3.1.1",
     "ansi_up": "6.0.6",