chore(deps-dev): bump tsdown from 0.12.3 to 0.15.6

Bumps [tsdown](https://github.com/rolldown/tsdown) from 0.12.3 to 0.15.6.
- [Release notes](https://github.com/rolldown/tsdown/releases)
- [Commits](rolldown/tsdown@v0.12.3...v0.15.6)

---
updated-dependencies:
- dependency-name: tsdown
  dependency-version: 0.15.6
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

package.json

@@ -43,7 +43,7 @@
     "@schemasset/utils": "workspace:*",
     "@types/node": "^22.15.16",
     "eslint": "^9.26.0",
-    "tsdown": "^0.12.3",
+    "tsdown": "^0.15.6",
     "tsx": "^4.19.4",
     "unbuild": "^3.5.0"
   }

packages/utils/package.json

@@ -22,7 +22,7 @@
   },
   "devDependencies": {
     "@oxc-project/runtime": "^0.72.0",
-    "tsdown": "^0.12.3",
+    "tsdown": "^0.15.6",
     "typescript": "^5.2.2"
   }
 }