Migrate webhook to unified review endpoint

[sylvansys]

Context

The Constellos MCP server now exposes a new POST /api/review/unified endpoint that replaces the need for the webhook to fetch .constellos/agents/code-quality.md from repos and send it as a prompt. The server handles everything: artifact type detection, review skill routing, constraint/decision context injection, and structured findings storage.

New Endpoint

POST mcp.constellos.ai/api/review/unified

Request

{
  "diff": "...",
  "changed_files": ["src/foo.ts", "supabase/migrations/001.sql"],
  "space": "constellos",
  "repo": "constellos/constellos",
  "pr_number": 123,
  "artifact_types": ["code", "database"],  // optional — auto-detected from changed_files
  "model": "deepseek/deepseek-reasoner"     // optional
}

Auth: X-Constellos-Secret header (same as existing endpoint).

Response

{
  "run_id": "uuid",
  "overall_passed": true,
  "phases": [
    {
      "phase": 5,
      "phase_name": "context_alignment",
      "status": "passed",
      "findings_count": 3,
      "started_at": "...",
      "completed_at": "..."
    }
  ],
  "findings": [
    {
      "id": "uuid",
      "skill_slug": "review-code-artifacts",
      "artifact_type": "code",
      "severity": "medium",
      "category": "quality",
      "source": "agent",
      "file_path": "src/foo.ts",
      "line_number": 42,
      "finding": "Description of the issue",
      "constraint_id": null,
      "decision_id": "uuid-of-violated-decision",
      "status": "open"
    }
  ],
  "skills_run": ["review-code-artifacts", "review-database-artifacts"],
  "constraint_findings": [...],
  "decision_findings": [...]
}

Migration Steps

1. Replace prompt fetching — No more fetching .constellos/agents/code-quality.md from repos. Send { diff, changed_files, space } and the server handles skill routing.

2. Format multi-agent comment — Group findings[] by skill_slug to create sections (e.g. "Code Review", "Database Review"). Each finding has severity, category, file_path, line_number for rich formatting.

3. Use run_id — Include in the PR comment for traceability back to the Constellos review run.

4. Backward compat — The existing POST /api/review endpoint still works unchanged. Migrate at your pace.

Key Improvements

• Multi-skill review: Automatically routes to appropriate review skills based on changed file types (.ts → code, .sql → database, .tsx → code+ui, etc.)
• Graph-aware: Queries governance constraints and decisions from the knowledge graph as review context
• Two-pass model: Pass 1 checks constraint compliance, Pass 2 verifies decision materialization
• Structured findings: Each finding has severity, category, file/line attribution, and constraint/decision traceability
• Persistent storage: All review runs, phases, and findings stored in review_runs/review_phases/review_findings tables