fix(turbopack): isolate runtime public path per bundle

[fireairforce]

Summary

• Capture globalThis.publicPath once for each runtime so another application cannot redirect later chunk and asset requests.
• Expose a writable runtime-local public path for Utoopack's __webpack_public_path__ compatibility transform.

Validation

• The dependent Utoopack regression fixture reproduced a request to the child application's URL before this change and passed after it.
• cargo clippy --all-targets -- -D warnings --no-deps passed in the Utoopack repository.

This runtime change is paired with utooland/utoo#3391, which updates the transform and adds the regression fixture.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-24T07:55:12.788536Z	c3c9b0b	PR opened

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