chore(deps): bump astro from 5.7.13 to 5.15.6 in /packages/web

Bumps [astro](https://github.com/withastro/astro/tree/HEAD/packages/astro) from 5.7.13 to 5.15.6.
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/main/packages/astro/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/astro@5.15.6/packages/astro)

---
updated-dependencies:
- dependency-name: astro
  dependency-version: 5.15.6
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

packages/web/package.json

@@ -19,7 +19,7 @@
     "@shikijs/transformers": "3.4.2",
     "@types/luxon": "3.6.2",
     "ai": "catalog:",
-    "astro": "5.7.13",
+    "astro": "5.15.6",
     "diff": "catalog:",
     "js-base64": "3.7.7",
     "lang-map": "0.4.0",