What does this PR do?

Fixes the current main test failure in tests/acp/test_mcp_e2e.py after the ACP prompt path started forwarding persist_user_message into AIAgent.run_conversation(...).

The production agent supports that keyword, but these local E2E test doubles had narrow mock signatures. This PR makes the mocks accept future optional keyword arguments so the tests continue to exercise ACP tool-call event behavior instead of failing at the adapter boundary.

Related Issue

Fixes current main CI regression from Tests run 25180124129.

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 🔒 Security fix
• 📝 Documentation update
• ✅ Tests (adding or improving test coverage)
• ♻️ Refactor (no behavior change)
• 🎯 New skill (bundled or hub)

Changes Made

• Updated two ACP MCP E2E run_conversation test doubles in tests/acp/test_mcp_e2e.py to accept **kwargs.
• Preserved the behavior under test: ACP tool start/result event emission and call-id pairing.

How to Test

1. Reproduce on current main: gh run view 25180124129 --repo NousResearch/hermes-agent --log-failed
2. Run the focused failing tests.
3. Run the full affected file with xdist.

Validation Status

Passed locally:

HOME="$TMP/home" HERMES_HOME="$TMP/hermes" CI=true TZ=UTC LANG=C.UTF-8 LC_ALL=C.UTF-8 PYTHONHASHSEED=0 \
  OPENROUTER_API_KEY='' OPENAI_API_KEY='' NOUS_API_KEY='' \
  /home/w0lf/hermes-agent/venv/bin/python -m pytest \
  tests/acp/test_mcp_e2e.py::TestMcpRegistrationE2E::test_prompt_with_tool_calls_emits_acp_events \
  tests/acp/test_mcp_e2e.py::TestMcpRegistrationE2E::test_prompt_tool_results_paired_by_call_id \
  -q -o addopts='' --tb=short
# 2 passed in 0.72s

HOME="$TMP/home" HERMES_HOME="$TMP/hermes" CI=true TZ=UTC LANG=C.UTF-8 LC_ALL=C.UTF-8 PYTHONHASHSEED=0 \
  OPENROUTER_API_KEY='' OPENAI_API_KEY='' NOUS_API_KEY='' \
  /home/w0lf/hermes-agent/venv/bin/python -m pytest tests/acp/test_mcp_e2e.py \
  -q -o addopts='' --tb=short -n 4
# 8 passed, 1 warning in 2.05s

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run pytest tests/ -q and all tests pass
• I've added tests for my changes (required for bug fixes, strongly encouraged for features)
• I've tested on my platform: Arch Linux, Python 3.14 local venv

Documentation & Housekeeping

• I've updated relevant documentation (README, docs/, docstrings) - N/A
• I've updated cli-config.yaml.example if I added/changed config keys - N/A
• I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows - N/A
• I've considered cross-platform impact (Windows, macOS) per the compatibility guide - test-only mock signature change, no runtime platform impact
• I've updated tool descriptions/schemas if I changed tool behavior - N/A

For New Skills

N/A

Screenshots / Logs

Current main failure:

TypeError: TestMcpRegistrationE2E.test_prompt_with_tool_calls_emits_acp_events.<locals>.mock_run_conversation() got an unexpected keyword argument 'persist_user_message'
TypeError: TestMcpRegistrationE2E.test_prompt_tool_results_paired_by_call_id.<locals>.mock_run() got an unexpected keyword argument 'persist_user_message'