feat: add unified-review workflow (scoring tools + skill)

Adds the unified-review integration that fuses CRG graph context with the
ai-code-review scoring methodology and gstack-review fix-first workflow:

- scoring.py: objective Layer-2 metrics (sql_risk, exception_coverage,
  redundancy_rate, high_risk_density, vulnerability_risk) with
  good/warn/fail grades, plus dedupe_findings (fingerprint merge,
  multi-source confidence boost, PR quality score) and report data builder
- tools/scoring_tools.py + main.py: three new MCP tools
  (score_review_tool, dedupe_findings_tool, generate_report_tool)
- assets/report-template.html: self-contained HTML report template
- skills.py + skills/unified-review/: new read-only unified-review skill
  with language/manual-review/specialist checklists
- docs and CHANGELOG updated; tests added (test_scoring, test_report,
  test_unified_review) and test_skills updated for 5 skills

code_review_graph/tools/docs.py

@@ -115,8 +115,8 @@ def get_docs_section(
 
     Args:
         section_name: Exact section name. One of: usage, review-delta,
-                      review-pr, commands, legal, watch, embeddings,
-                      languages, troubleshooting.
+                      review-pr, unified-review, score-review, commands,
+                      legal, watch, embeddings, languages, troubleshooting.
         repo_root: Repository root path. Auto-detected from current
                    directory if omitted.
 
@@ -177,8 +177,9 @@ def get_docs_section(
                 }
 
     available = [
-        "usage", "review-delta", "review-pr", "commands",
-        "legal", "watch", "embeddings", "languages", "troubleshooting",
+        "usage", "review-delta", "review-pr", "unified-review",
+        "score-review", "commands", "legal", "watch", "embeddings",
+        "languages", "troubleshooting",
     ]
     return {
         "status": "not_found",