chore(release): bump version to v3.7.0 and rebrand to include Gemini CLI

- Update version from 3.6.2 to 3.7.0 across all config files
- Update project description to "All-in-One Assistant for Claude Code, Codex & Gemini CLI"
- Update Chinese description to "Claude Code / Codex / Gemini CLI 全方位辅助工具"
- Sync version in package.json, Cargo.toml, tauri.conf.json
- Update branding in README.md, README_ZH.md and i18n locale files

package.json

@@ -1,7 +1,7 @@
 {
   "name": "cc-switch",
-  "version": "3.6.2",
-  "description": "Claude Code & Codex 供应商切换工具",
+  "version": "3.7.0",
+  "description": "All-in-One Assistant for Claude Code, Codex & Gemini CLI",
   "scripts": {
     "dev": "pnpm tauri dev",
     "build": "pnpm tauri build",