feat: 添加 Provider Registry、StatusLine、Cache Stats 和其他增强

- providerRegistry: OpenAI 兼容 provider 切换（Cerebras/Groq/DeepSeek/Qwen）
- StatusLine: 增强状态栏（缓存命中率、TTL 倒计时、自定义 shell 命令）
- cacheStats: 缓存命中率和 token 签名追踪
- ultrareviewPreflight: 代码审查预检服务
- SkillsMenu/filterSkills: 技能菜单过滤增强
- MagicDocs/langfuse prompts: 提示词更新
- claude.ts: API 客户端更新

Co-Authored-By: glm-5-turbo <zai-org@claude-code-best.win>

src/keybindings/validate.ts

@@ -71,9 +71,12 @@ const VALID_CONTEXTS: KeybindingContextName[] = [
   'Tabs',
   'Attachments',
   'Footer',
+  'FormField',
+  'MessageActions',
   'MessageSelector',
   'DiffDialog',
   'ModelPicker',
+  'Scroll',
   'Select',
   'Plugin',
 ]