chore: bump tsdown from 0.18.3 to 0.18.4 (#98)

Bumps [tsdown](https://github.com/rolldown/tsdown) from 0.18.3 to 0.18.4.
- [Release notes](https://github.com/rolldown/tsdown/releases)
- [Commits](rolldown/tsdown@v0.18.3...v0.18.4)

---
updated-dependencies:
- dependency-name: tsdown
  dependency-version: 0.18.4
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

package.json

@@ -5,7 +5,7 @@
         "@apst/tsconfig": "~0.1.3",
         "@apst/tsdown": "~0.1.0",
         "@biomejs/biome": "^2.3.10",
-        "tsdown": "~0.18.3",
+        "tsdown": "~0.18.4",
         "typedoc": "~0.28.15",
         "typedoc-plugin-markdown": "^4.9.0",
         "typescript": "^5.9.3"