feat(P02): backend-enriched tier, chaos engineering, prioritization — IDEATE-04,05,06,09,10

---ci---
phase: 2
milestone: v0.10
status: execute
decisions:
  - id: D-087
    decision: All 6 innovative features in v1 (pattern mining, drift detection, layer inversion, cross-project, chaos, spec)
    rationale: User wants bleeding-edge; all uniquely differentiated
    confidence: 0.82
requirements:
  covered:
    - IDEATE-04
    - IDEATE-05
    - IDEATE-06
    - IDEATE-09
    - IDEATE-10
---/ci---

- IDEATE-04: Verification layer inversion (structural, behavioral, security, quality missing detection)
- IDEATE-05: Architectural drift detection (documented vs actual component comparison)
- IDEATE-06: Spec-driven improvement (ambiguity detection, missing category detection)
- IDEATE-09: Backend-enriched analysis (prioritization, novel suggestions, action plans)
- IDEATE-10: Chaos engineering ideation (backend unavailable, requirement change, coverage drop)
- Deduplicated type exports: IdeationSource/Idea/etc now in types/ideation.ts
- 538 tests passing

src/core/ideation.test.ts

@@ -2,7 +2,8 @@ import * as fs from "node:fs";
 import * as path from "node:path";
 import * as os from "node:os";
 import { IdeationAgent } from "../agents/ideation-agent.js";
-import { IdeationEngine, resetIdeaCounter, Idea } from "../core/ideation.js";
+import { IdeationEngine, resetIdeaCounter } from "../core/ideation.js";
+import { Idea, IdeationAction, DEFAULT_IDEATION_CONFIG } from "../types/ideation.js";
 
 describe("IdeationAgent", () => {
   let tempDir: string;
@@ -244,4 +245,86 @@ describe("IdeationEngine", () => {
       expect(results.every((r) => r.addedToRequirements || r.addedToRoadmap)).toBe(true);
     });
   });
+
+  describe("Phase 2: Backend-enriched and chaos", () => {
+    let tempDir: string;
+
+    beforeEach(() => {
+      resetIdeaCounter();
+      tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "ciagent-p2-test-"));
+    });
+
+    afterEach(() => {
+      fs.rmSync(tempDir, { recursive: true, force: true });
+    });
+
+    it("runBackendEnriched prioritizes mechanical findings", () => {
+      const engine = new IdeationEngine(tempDir);
+      const mechanicalIdeas: Idea[] = [
+        {
+          id: "IDEATE-01",
+          source: "uncovered_requirement",
+          category: "coverage",
+          title: "Missing test",
+          rationale: "No test file",
+          confidence: 0.7,
+          actions: ["add_test"],
+          tier: "mechanical",
+        },
+        {
+          id: "IDEATE-02",
+          source: "escalation_pattern",
+          category: "security",
+          title: "Security issue",
+          rationale: "Repeated escalation",
+          confidence: 0.8,
+          actions: ["add_security_pattern"],
+          tier: "mechanical",
+        },
+      ];
+
+      const enriched = engine.runBackendEnriched(mechanicalIdeas);
+      expect(enriched.length).toBeGreaterThanOrEqual(2);
+      const prioritizedIdeas = enriched.filter((i) => i.source === "uncovered_requirement" || i.source === "escalation_pattern");
+      expect(prioritizedIdeas.length).toBeGreaterThanOrEqual(2);
+      for (const idea of prioritizedIdeas) {
+        expect(idea.tier).toBe("backend-enriched");
+      }
+    });
+
+    it("runBackendEnriched adds novel suggestions for missing categories", () => {
+      const engine = new IdeationEngine(tempDir);
+      const mechanicalIdeas: Idea[] = [
+        {
+          id: "IDEATE-01",
+          source: "uncovered_requirement",
+          category: "coverage",
+          title: "Cover this",
+          rationale: "Missing",
+          confidence: 0.7,
+          actions: ["add_test"],
+          tier: "mechanical",
+        },
+      ];
+
+      const enriched = engine.runBackendEnriched(mechanicalIdeas);
+      const novelIdeas = enriched.filter((i) => i.source === "improvement_pattern");
+      expect(novelIdeas.length).toBeGreaterThanOrEqual(1);
+    });
+
+    it("generateChaosScenarios uses default scenarios when enabled", () => {
+      const engine = new IdeationEngine(tempDir);
+      const chaosIdeas = engine.generateChaosScenarios();
+
+      expect(chaosIdeas.length).toBe(3);
+      expect(chaosIdeas.every((i) => i.source === "chaos_scenario")).toBe(true);
+      expect(chaosIdeas.every((i) => i.category === "chaos")).toBe(true);
+      expect(chaosIdeas.every((i) => i.tier === "backend-enriched")).toBe(true);
+      expect(chaosIdeas.every((i) => i.confidence >= 0.5)).toBe(true);
+      const titles = chaosIdeas.map((i) => i.title);
+      expect(titles.some((t) => t.includes("backend"))).toBe(true);
+      expect(titles.some((t) => t.includes("requirement"))).toBe(true);
+      expect(titles.some((t) => t.includes("coverage"))).toBe(true);
+    });
+  });
 });