fix(client): preserve URL components when appending endpoint paths - #753

When a proxy base_url contains a query string or fragment, URL construction appends the endpoint to the raw URL rather than its path. For example, listing organizations against https://proxy.example/prefix?route=a%2Fb sends a request to /prefix and moves /organizations into the query. SSO/AuthKit authorization URLs have the same problem. Per-request base_url overrides are affected too.

Join the endpoint onto the parsed path, preserve the existing query and fragment, and append encoded operation parameters to the query. Normalize a trailing slash on the path rather than appending it after a query or fragment. Existing no-query/no-fragment behavior is covered by controls.

This changes only the hand-maintained @oagen-ignore-file base client and a similarly marked test file. Generated resources, schemas, authentication logic, and version/release files are untouched.

Thirty public-client regression/control cases cover sync/async organization requests, constructor and per-request base URLs, and SSO/AuthKit authorization URLs, using an httpx2.MockTransport for HTTP requests. Eighteen fail before the fix; twelve controls pass. All 2,994 repository tests pass after the change. Repository-wide Ruff lint/format and Pyright pass (zero errors/warnings). Wheel and source distribution builds pass independently with a fresh cache; the initial combined uv build failed while extracting an archive. No live WorkOS request or account was used. Developed with AI assistance and verified locally.