chore: 同步 v5.0 基础设施完善到 v5.1

从 v5.0 cherry-pick 的开源项目基础设施改进:

新增配置文件:
- .editorconfig, .gitattributes, .prettierrc, .markdownlint.json
- commitlint.config.js

新增 GitHub 社区文件:
- .github/dependabot.yml — 依赖自动更新
- .github/CODEOWNERS — 自动 PR 审查分配
- .github/FUNDING.yml — 开源赞助入口

新增文档:
- ROADMAP.md — 路线图
- SUPPORT.md — 帮助指南
- docs/screenshots/ — 应用截图

新增 Git Hooks:
- .husky/pre-commit — lint-staged 自动格式化+修复
- .husky/commit-msg — commitlint 校验

CI 强化:
- 新增 Prettier 格式检查
- 新增 Vitest 覆盖率 + Codecov 上报
- 保留 v5.1 已有的 rust-cache + jsdom 全局环境

修复:
- index.html 标题 v4.0 → v5.1
- PathEditDialog set-state-in-effect 改用 useRef prevOpen 守卫
- merge-preview.test.tsx no-explicit-any 修复
- 所有 TS/TSX 文件 Prettier 格式化统一

v5.1 保留特性:
- @tanstack/react-virtual 虚拟滚动
- jsdom 全局测试环境
- Swatinem/rust-cache CI 加速
- 105 测试全部通过

.github/dependabot.yml

@@ -0,0 +1,73 @@
+# Dependabot 自动依赖更新配置
+# https://docs.github.com/code-security/dependabot/dependabot-version-updates
+
+version: 2
+updates:
+  # npm 前端依赖
+  - package-ecosystem: "npm"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+      time: "09:00"
+      timezone: "Asia/Shanghai"
+    versioning-strategy: "auto"
+    allow:
+      - dependency-type: "all"
+    labels:
+      - "dependencies"
+      - "javascript"
+    commit-message:
+      prefix: "chore(deps)"
+      prefix-development: "chore(deps-dev)"
+    open-pull-requests-limit: 5
+    groups:
+      react:
+        patterns:
+          - "react"
+          - "react-dom"
+          - "@types/react"
+          - "@types/react-dom"
+      tauri:
+        patterns:
+          - "@tauri-apps/*"
+      testing:
+        patterns:
+          - "@testing-library/*"
+          - "@playwright/test"
+          - "vitest"
+          - "jsdom"
+      eslint:
+        patterns:
+          - "eslint"
+          - "eslint-plugin-*"
+          - "typescript-eslint"
+          - "globals"
+          - "@eslint/js"
+
+  # Cargo Rust 依赖
+  - package-ecosystem: "cargo"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+      time: "09:00"
+      timezone: "Asia/Shanghai"
+    labels:
+      - "dependencies"
+      - "rust"
+    commit-message:
+      prefix: "chore(deps)"
+      prefix-development: "chore(deps-dev)"
+    open-pull-requests-limit: 3
+
+  # GitHub Actions
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "monthly"
+    labels:
+      - "dependencies"
+      - "ci"
+    commit-message:
+      prefix: "ci(deps)"