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

src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "CC Switch",
-  "version": "3.6.2",
+  "version": "3.7.0",
   "identifier": "com.ccswitch.desktop",
   "build": {
     "frontendDist": "../dist",