This reverts commit 4747fe2.

…g tag check

This ensures that when rootElement is undefined no error occures.

…inst SSRF and path hijack

Normalizes the URL and path parsing logic inside platform-server by consolidating security checks and normalizations into a single, unified parseUrl helper function.

This includes:
- Collapsing multiple consecutive leading slashes and backslashes (e.g., // or /\) to a single forward slash to avoid protocol-relative parsing of path-like & relative inputs.
- Rejecting malformed absolute URLs that are otherwise accepted by lenient DOM parsers like Domino but rejected by standard WHATWG parsers, preventing SSRF / allowedHosts validation bypasses.
- Ensuring parseDocument gets the fully parsed and normalized URL instead of raw, unvalidated configuration values, preventing virtual document hostname adoption/origin hijack.
- Moving parseUrl unit tests into a dedicated url_spec.ts test file to keep platform_location_spec.ts clean and decoupled.