chore: split mcp/tools.py into focused submodules — 1448 → 240 lines (AC-482)

[jayscambler]

Summary

Split mcp/tools.py (1,448 lines, 62 functions) into 5 focused submodules plus a shared base, reducing it to 240 lines (83% reduction).

New structure

mcp/
├── _base.py              (67 lines)  — MtsToolContext + shared helpers
├── tools.py              (240 lines) — scenario tools + skill tools + re-exports
├── agent_task_tools.py   (454 lines) — create/evaluate/queue agent tasks
├── knowledge_tools.py    (334 lines) — playbook/trajectory/skill reads + exports
├── artifact_tools.py     (229 lines) — publish/fetch/validate artifacts
├── distill_tools.py      (167 lines) — distillation workflow management
├── monitor_tools.py      (85 lines)  — monitor conditions/alerts
├── server.py             (642 lines) — unchanged
└── sandbox.py            (206 lines) — unchanged

Backward compatibility

tools.py re-exports all extracted functions via # noqa: F401 imports, so all existing consumers (server/openclaw_api.py, cli.py, knowledge/, openclaw/) continue to work without changes.

Also fixed

• Updated sdk.py to import from specific submodules instead of via tools module attribute access
• Updated tests/test_sdk.py patches to match new import paths

Verification

• ruff check src — all checks passed
• mypy src — zero errors
• pytest tests/ — all tests pass

Issue

Continues AC-482 (stages.py done in #586, mcp/tools.py done here, cli.py deferred)

[linear]

AC-482 Break up god files: stages.py (2591), mcp/tools.py (1449), cli.py (1504)