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

[ajianaz]

MCP Phase 1 — Code Intelligence Tools

Expose v0.6/v0.7 code intelligence features to AI agents via MCP.

Tools to add:

Tool	Input	Description
cora.search_symbols	query, kind?, file?, language?, limit?	FTS5 search across symbol index
cora.find_callers	symbol, limit?	Reverse call graph — who calls this?
cora.find_impact	symbol, depth?	Blast radius — what breaks if changed?
cora.find_affected_tests	files[]	Test selection — which tests to run?
cora.index_status	—	Index stats + freshness check

Design:

• Read-only (no side effects)
• JSON output for agent parsing
• Graceful degradation ("no index, run cora index first")
• Fast: <100ms (no LLM calls)
• Stateless

Depends on:

• feat: cora index — Symbol index & SQLite persistence #264 cora index ✅ Done
• feat: cora callers / cora impact — Call graph query commands #266 cora callers/impact ✅ Done
• feat: cora affected — Find tests affected by changes #267 cora affected ✅ Done

[ajianaz]

Shipped in PR #287. 5 MCP tools added, runtime verified, 559 tests pass.