* fix: guard integration HTTP requests against SSRF
* fix(openclaw): complete fallback validation and base URL handling
Address the remaining review findings in the OpenClaw integration.
- Strengthen fallback base_url validation to require a non-empty string, valid HTTP(S) scheme, netloc, and hostname.
- Strip leading and trailing whitespace from base_url before storing it.
- Replace the flaky endpoint-construction test that made a real network connection with mocked session assertions.
- Add coverage for _get and _post endpoint construction and timeout forwarding.
- Add regression tests for whitespace-padded base URLs and the fallback validation path.
These changes complete the Qodo review fixes and harden OpenClaw URL handling without changing the intended localhost/private deployment behavior.
