Phase 8: Implement coverage scorer on /query and MCP inject

[cursor]

Background

Architecture and UI already expect a per-query coverage_score. Schema indices exist (V005__coverage_indices.cypher). No scorer implementation yet.

Problem Statement

Agents and the dashboard cannot tell when organizational memory is thin for a domain.

Proposed Solution

• Implement coverage scorer (domain completeness estimate)
• Return coverage_score on every /query (and inject) response
• Surface via MCP if/when inject/query tools are used
• Wire existing frontend fields in Ask/Home views

Acceptance Criteria

• Coverage scorer module with unit tests
• /query (and inject path) returns real coverage_score (0–1)
• Dashboard displays coverage without placeholder/undefined
• Documented in README API table / docs

Files / Modules Affected

scoring/ or intelligence/, api/memory.py, api/schemas.py, mcp/server.js, frontend/src/views/AskView.tsx, frontend/src/views/HomeView.tsx, graph migrations as needed

Phase: 8 — Outcome tracking + coverage scoring