SUB STORE 项目重构

`ref/sub-store-cloudflare` 是一个使用cloudflare部署的机场订阅转换助手，我们需要参考原项目，完成GO语言、SQLITE数据库的重构。

## 项目约束

- **全新项目，无历史数据包袱**：不存在存量用户、存量配置、存量过滤器需要迁移。所有"向后兼容"、"存量 script 过滤器迁移"、"process→FilterRule 转换"等问题均不需要考虑——直接按 Go 版自身的设计实现即可，不必复刻原项目的兼容逻辑。
- **ProxyNode 类型自由选择**：不强制与原项目 `Record<string, unknown>` 保持一致，按 Go 最佳实践选择 struct 或 map。
- **前端适配后端**：前端尚未实现，后端 API 设计可自由定义，不需要兼容原前端格式。

## 开发决议

开发前必读 [`docs/review-resolutions.md`](docs/review-resolutions.md) — 45 条 review 问题的逐条决议（ProxyNode 类型、token 双哈希、SQLite PRAGMA、sing-box 完整结构等）。开发中不得偏离已定决议；如需变更，先改本文档再改代码。

**关键决议摘要**：

- ProxyNode = `map[string]any`，深拷贝用 json.Marshal/Unmarshal
- token 校验先 SHA-256 再 ConstantTimeCompare（防长度泄露时序攻击）
- SQLite: WAL + busy_timeout=5000 + foreign_keys=ON + MaxOpenConns=1
- CSP 收紧为 `script-src 'self'`（无 unsafe-eval）
- custom 规则链上限 32 条，替代 JS script 过滤器
- modernc.org/sqlite（纯 Go），接受写性能 tradeoff

## 验收标准

- 单元测试覆盖率 ≥ 85%

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## CodeGraph

This project has a CodeGraph MCP server (`codegraph_*` tools) configured. CodeGraph is a tree-sitter-parsed knowledge graph of every symbol, edge, and file. Reads are sub-millisecond and return structural information grep cannot.

### When to prefer codegraph over native search

Use codegraph for **structural** questions — what calls what, what would break, where is X defined, what is X's signature. Use native grep/read only for **literal text** queries (string contents, comments, log messages) or after you already have a specific file open.

| Question                                      | Tool                |
| --------------------------------------------- | ------------------- |
| "Where is X defined?" / "Find symbol named X" | `codegraph_search`  |
| "What calls function Y?"                      | `codegraph_callers` |
| "What does Y call?"                           | `codegraph_callees` |
| "What would break if I changed Z?"            | `codegraph_impact`  |
| "Show me Y's signature / source / docstring"  | `codegraph_node`    |
| "Give me focused context for a task/area"     | `codegraph_context` |
| "Survey an unfamiliar module/topic"           | `codegraph_explore` |
| "What files exist under path/"                | `codegraph_files`   |
| "Is the index healthy?"                       | `codegraph_status`  |

### Rules of thumb

- **Trust codegraph results.** They come from a full AST parse. Do NOT re-verify them with grep — that's slower, less accurate, and wastes context.
- **Don't grep first** when looking up a symbol by name. `codegraph_search` is faster and returns kind + location + signature in one call.
- **Don't chain `codegraph_search` + `codegraph_node`** when you just want context — `codegraph_context` is one call.
- **`codegraph_explore` is the heavy hitter** for unfamiliar areas — it returns full source from all relevant files in one call, but is token-heavy. If your harness supports parallel subagents (e.g., Claude Code's Task tool), spawn one for explore-class questions to keep main session context clean.
- **Index lag**: the file watcher debounces ~500ms behind writes; don't re-query immediately after editing a file in the same turn.

### If `.codegraph/` doesn't exist

The MCP server returns "not initialized." Ask the user: _"I notice this project doesn't have CodeGraph initialized. Want me to run `codegraph init -i` to build the index?"_

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