Summary

Support full URLs in api_host, following the behavior discussed in #157:

• Map HTTP/WS inputs to HTTP probes and WS sessions, and HTTPS/WSS inputs to HTTPS probes and WSS sessions.
• Preserve existing host:port inputs, IPv6 addresses, encoded reverse-proxy path prefixes and query strings.
• Reject unsupported URL schemes before network I/O and add a TLS-configuration hint to secure connection failures.
• Use the same URL construction in the synchronous and asynchronous session paths.

Validation

• pytest tests -m 'not lmstudio' -q: 207 passed, 202 deselected, including 30 new offline cases.
• ruff check --config pyproject.toml src/lmstudio/json_api.py src/lmstudio/sync_api.py src/lmstudio/async_api.py tests/test_api_host_urls.py: passed.
• ruff format --config pyproject.toml --check on the same four files: passed.
• mypy --strict on the same four files: passed.

Checked on macOS with Python 3.12.13 and the locked pytest 8.4.1 / Ruff 0.12.10 versions. No live LM Studio server or TLS reverse proxy was used; those integration tests remain unverified locally. No custom TLS configuration is introduced.

Prepared with Codex assistance and independently reviewed, including the actual sync/async HTTPX transport paths with network access blocked.

Fixes #157