chore: bootstrap project scaffolding

Add architecture doc (research-wiki/ARCHITECTURE.md), CLAUDE.md with
tiered SOP for Fable 5, adapted .claude skills/hooks/settings, package
skeleton (src/polygateway), pyproject with import-linter contracts,
Makefile, .env.example and smoke test.

.claude/templates/IDEA_CANDIDATES_CN.md

@@ -0,0 +1,30 @@
+# Idea 候选池模板
+
+> 用于跟踪当前候选方案、淘汰原因和切换历史。
+
+## 当前 Idea
+
+[填写：当前正在推进的 idea 名称、核心假设和一句话概述。]
+
+## 候选列表
+
+| Idea 名称 | 一句话描述 | 新颖性评分 (X/10) | 评审意见 | 试点结果 | 预估工作量 | 未优先选择原因 |
+|---|---|---:|---|---|---|---|
+| [填写] | [填写] | [填写] | [填写] | [填写] | [填写] | [填写] |
+| [填写] | [填写] | [填写] | [填写] | [填写] | [填写] | [填写] |
+| [填写] | [填写] | [填写] | [填写] | [填写] | [填写] | [填写] |
+
+## 已淘汰 Idea
+
+| Idea 名称 | 淘汰原因 | 日期 | 来源 |
+|---|---|---|---|
+| [填写] | [填写] | [填写] | [填写] |
+| [填写] | [填写] | [填写] | [填写] |
+
+## Idea 切换日志
+
+| 日期 | 从 | 到 | 原因 |
+|---|---|---|---|
+| [填写] | [填写] | [填写] | [填写] |
+| [填写] | [填写] | [填写] | [填写] |
+