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/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "cc-switch"
-version = "3.6.2"
-description = "Claude Code & Codex 供应商配置管理工具"
+version = "3.7.0"
+description = "All-in-One Assistant for Claude Code, Codex & Gemini CLI"
 authors = ["Jason Young"]
 license = "MIT"
 repository = "https://github.com/farion1231/cc-switch"