FEL-642: add typed browser client APIs

[codeyousef]

Summary

• add a typed, same-origin browser HTTP client for JS and Wasm-JS
• add bounded bootstrap and typed history/location APIs
• cover success, failure, timeout, redirect, size-limit, cancellation, CSRF, and navigation behavior
• lock the new module dependencies and extend the expected-source verification surface

Verification

• ./gradlew verifyExpectedSourceTasks
• ./gradlew :aether-browser-client:check
• git diff --check

Release boundary

This PR deliberately adds the API without changing the current release version or Central publication manifest. A future Aether release will add the three browser-client coordinates and update the immutable manifest checks before these artifacts are published.