docs: initialize dev-workflow project with GSD

- PROJECT.md: 项目愿景和核心价值
- REQUIREMENTS.md: 21个v1需求 + 4个v2延期需求
- ROADMAP.md: 11阶段开发路线图
- STATE.md: 项目状态跟踪
- config.json: GSD工作流配置

.planning/config.json

@@ -0,0 +1,13 @@
+{
+  "mode": "interactive",
+  "granularity": "standard",
+  "parallelization": true,
+  "commit_docs": true,
+  "model_profile": "balanced",
+  "workflow": {
+    "research": true,
+    "plan_check": true,
+    "verifier": true,
+    "nyquist_validation": true
+  }
+}