docs: sync Claude Tier 2 skill with Gemini — add atomic commits and sanity check rules

Port two responsibilities from Gemini's mma-tier2-tech-lead SKILL.md (b4de62f, 7afa3f3)
to Claude's equivalent command file:
- ATOMIC PER-TASK COMMITS: enforce per-task commit discipline
- Meta-Level Sanity Check: ruff + mypy post-track verification

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.claude/commands/mma-tier2-tech-lead.md

@@ -15,6 +15,8 @@ Read at session start: `conductor/tech-stack.md`, `conductor/workflow.md`
 - Break down tasks into specific technical steps for Tier 3 Workers
 - Maintain PERSISTENT context throughout a track's implementation phase (NO Context Amnesia)
 - Review implementations and coordinate bug fixes via Tier 4 QA
+- **CRITICAL: ATOMIC PER-TASK COMMITS**: You MUST commit your progress on a per-task basis. Immediately after a task is verified successfully, you must stage the changes, commit them, attach the git note summary, and update `plan.md` before moving to the next task. Do NOT batch multiple tasks into a single commit.
+- **Meta-Level Sanity Check**: After completing a track (or upon explicit request), perform a codebase sanity check. Run `uv run ruff check .` and `uv run mypy --explicit-package-bases .` to ensure Tier 3 Workers haven't degraded static analysis constraints. Identify broken simulation tests and append them to a tech debt track or fix them immediately.
 
 ## Delegation Commands (PowerShell)