feat: Simplify agent architecture with test-fix workflow (v3.2.0)

Major architectural improvements:
- Simplify from 3 agents to 2 core agents
- Adopt "Tests Are the Review" philosophy
- Enhance test-gen as 4-phase orchestrator
- Simplify review.md following update-memory pattern

Agent Changes:
- NEW: @test-fix-agent - Execute tests, diagnose failures, fix code
- ENHANCED: @code-developer - Now writes implementation + tests together
- REMOVED: @code-review-agent, @code-review-test-agent

Task Type Updates:
- "test" → "test-gen" (generate tests)
- NEW: "test-fix" (execute and fix tests)

Workflow Improvements:
- test-gen.md: 4-phase orchestrator (context-gather → concept-enhanced → task-generate → execute)
- review.md: Simplified to optional specialized reviews (security, architecture, quality, action-items)
- All 16 files updated with new agent references

See CHANGELOG.md for full details.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.claude/commands/task/breakdown.md

@@ -88,8 +88,9 @@ Files updated: .task/IMPL-1.json + 2 subtask files + TODO_LIST.md
 ### Agent Assignment
 - **Design/Planning** → `@planning-agent`
 - **Implementation** → `@code-developer`
-- **Testing** → `@code-review-test-agent`
-- **Review** → `@review-agent`
+- **Testing** → `@code-developer` (type: "test-gen")
+- **Test Validation** → `@test-fix-agent` (type: "test-fix")
+- **Review** → `@general-purpose` (optional)
 
 ### Context Inheritance
 - Subtasks inherit parent requirements
@@ -161,8 +162,8 @@ See @~/.claude/workflows/workflow-architecture.md for:
 
 ▸ impl-1: Build authentication (container)
   ├── impl-1.1: Design schema → @planning-agent
-  ├── impl-1.2: Implement logic → @code-developer
-  └── impl-1.3: Write tests → @code-review-test-agent
+  ├── impl-1.2: Implement logic + tests → @code-developer
+  └── impl-1.3: Execute & fix tests → @test-fix-agent
 ```
 
 ## Error Handling