Add configurable browser API adapters

[waple0820]

Summary

• add a data-driven adapter library for known website API endpoints
• expose configurable Agent kwargs for adapter hints and the browser_api_call action
• add a browser-context API action that reuses page cookies and records adapter success/failure

Tests

• uv run pytest tests/ci/test_agent_adapters.py
• PATH=/Users/avatar/.local/share/uv/python/cpython-3.11.14-macos-aarch64-none/bin:$PATH uv run pre-commit run --all-files

Bench validation

• Used browseruse-bench-staging with the sibling environment config and local browser-use via PYTHONPATH
• LexBench-Browser task_id=245 completed with agent_done=done, agent_success=true, browser_id=lexmount, model_id=deepseek-v4-pro