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

tests/test_unified_review.py

@@ -0,0 +1,67 @@
+"""Tests for unified-review MCP tool wiring (registration + docs sections)."""
+
+from __future__ import annotations
+
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).parent.parent))
+
+from code_review_graph.tools import (  # noqa: E402
+    dedupe_findings_func,
+    generate_report_func,
+    score_review_func,
+)
+from code_review_graph.tools.docs import get_docs_section  # noqa: E402
+
+
+class TestToolRegistration:
+    def test_scoring_funcs_exported(self):
+        assert callable(score_review_func)
+        assert callable(dedupe_findings_func)
+        assert callable(generate_report_func)
+
+    def test_mcp_tools_exposed(self):
+        import code_review_graph.main as m
+
+        for name in (
+            "score_review_tool",
+            "dedupe_findings_tool",
+            "generate_report_tool",
+        ):
+            assert hasattr(m, name), f"{name} not exposed by main module"
+
+
+class TestDocsSections:
+    def test_unified_review_section(self):
+        result = get_docs_section("unified-review")
+        assert result["status"] == "ok"
+        assert "score_review_tool" in result["content"]
+
+    def test_score_review_section(self):
+        result = get_docs_section("score-review")
+        assert result["status"] == "ok"
+        assert "dedupe_findings_tool" in result["content"]
+
+    def test_unknown_section(self):
+        result = get_docs_section("does-not-exist")
+        assert result["status"] == "not_found"
+        assert "unified-review" in result["error"]
+
+
+class TestGenerateSkills:
+    def test_unified_review_generated(self, tmp_path):
+        from code_review_graph.skills import generate_skills
+
+        skills_dir = generate_skills(tmp_path)
+        skill_file = skills_dir / "unified-review" / "SKILL.md"
+        assert skill_file.is_file()
+        content = skill_file.read_text(encoding="utf-8")
+        assert "score_review_tool" in content
+        assert "get_minimal_context" in content
+        assert "detail_level" in content
+
+    def test_uninstall_knows_unified_review(self):
+        from code_review_graph.uninstall import _generated_skill_slugs
+
+        assert "unified-review" in _generated_skill_slugs()