feat: MCP Phase 2 — Review + Debt tools (2 tools)

[ajianaz]

MCP Phase 2 — Review Pipeline Integration

Allow AI agents to trigger reviews and check tech debt via MCP.

Tools to add:

Tool	Input	Description
cora.review_diff	diff, severity?	Trigger LLM review on a diff string
cora.get_debt	since?, branch?	Tech debt report (quality score, findings, trend)

Design:

• review_diff makes LLM call (agent should know it takes time)
• get_debt is fast (reads local snapshot history)
• JSON output
• Read-only

Depends on:

• feat: MCP Phase 1 — Code Intelligence tools (5 tools) #284 MCP Phase 1

[ajianaz]

Shipped in PR #288