Replace **kwargs with explicit parameters in test mocks

[alexkroman]

Replace catch-all **kwargs and **_kwargs parameters with explicit keyword-only parameters in test mock functions to improve type safety and clarity.

Summary

This change systematically updates test mock functions across the test suite to use explicit keyword-only parameters instead of catch-all **kwargs or **_kwargs. This improves code clarity, enables better type checking, and makes the expected function signatures more discoverable.

Key Changes

• test_stream_command.py: Updated mock stream_audio functions to explicitly declare on_begin, on_turn, and on_termination parameters instead of **_kwargs
• test_stream_session.py: Same pattern applied to stream session mocks
• test_stream_llm.py: Updated LLM streaming mocks with explicit callback parameters
• test_agent_command.py: Updated run_session mocks to explicitly declare renderer, player, mic, and config parameters
• test_onboard_sections.py: Expanded _fake_run_init and _fake_launch to explicitly list all expected keyword arguments
• test_update_check.py: Updated fake_get and fake_popen to use explicit parameters (headers, timeout, follow_redirects, stdout, stderr, start_new_session, env)
• test_login.py: Refactored login result helpers to use explicit json_mode parameter
• test_coding_agent.py: Updated subprocess mocks with explicit timeout parameter
• test_deploy.py: Updated fake_confirm and fake_run with explicit parameters
• test_macos_audio_source.py: Updated subprocess mock with explicit capture_output, text, and check parameters
• test_stream_command_flags.py: Updated stream audio mock with explicit callback parameters
• test_context.py: Updated login mock with explicit json_mode parameter
• test_init_template_serve.py: Updated HTTP mock with explicit parameters
• test_login_guards.py: Removed unused **_kwargs from login result helper
• test_output.py: Updated status context manager mock with explicit message parameter
• test_streaming_sources.py: Updated subprocess mock with explicit stdout and stderr parameters

Implementation Details

All changes maintain backward compatibility with the calling code while making the function signatures more explicit and type-safe. This pattern aligns with the project's emphasis on strict typing and clarity in test code.

https://claude.ai/code/session_01XVarv54ryA8Eo9zohCKx77