build(deps): bump undici and miniflare

Bumps [undici](https://github.com/nodejs/undici) to 7.29.0 and updates ancestor dependency [miniflare](https://github.com/cloudflare/workers-sdk/tree/HEAD/packages/miniflare). These dependencies need to be updated together.


Updates `undici` from 7.28.0 to 7.29.0
- [Release notes](https://github.com/nodejs/undici/releases)
- [Commits](nodejs/undici@v7.28.0...v7.29.0)

Updates `miniflare` from 4.20260730.0 to 5.20260811.1-alpha
- [Release notes](https://github.com/cloudflare/workers-sdk/releases)
- [Changelog](https://github.com/cloudflare/workers-sdk/blob/main/packages/miniflare/CHANGELOG.md)
- [Commits](https://github.com/cloudflare/workers-sdk/commits/miniflare@5.20260811.1-alpha/packages/miniflare)

---
updated-dependencies:
- dependency-name: miniflare
  dependency-version: 5.20260811.0-alpha
  dependency-type: direct:development
- dependency-name: undici
  dependency-version: 7.29.0
  dependency-type: indirect
...

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

Author: dependabot[bot]

package-lock.json

@@ -77,7 +77,7 @@
     "jest": "30.4.2",
     "jest-fetch-mock": "^3.0.3",
     "jose": "^6.2.0",
-    "miniflare": "^4.20260302.0",
+    "miniflare": "^5.20260811.1-alpha",
     "prettier": "^3.5.3",
     "publint": "^0.3.18",
     "tsdown": "^0.22.0",