refactor: remove OMO common config two-layer merge system

Each OMO provider now stores its complete configuration directly in
settings_config.otherFields instead of relying on a shared OmoGlobalConfig
merged at write time. This simplifies the data flow from a 4-tuple
(agents, categories, otherFields, useCommonConfig) to a 3-tuple and
eliminates an entire DB table, two Tauri commands, and ~1700 lines of
merge/sync code across frontend and backend.

Backend:
- Delete database/dao/omo.rs (OmoGlobalConfig struct + get/save methods)
- Remove get/set_config_snippet from settings DAO
- Remove get/set_common_config_snippet Tauri commands
- Replace merge_config() with build_config() in services/omo.rs
- Simplify OmoVariant (remove config_key, known_keys)
- Simplify import_from_local and build_local_file_data
- Rewrite all OMO service tests

Frontend:
- Delete OmoCommonConfigEditor.tsx and OmoGlobalConfigFields.tsx
- Delete src/lib/api/config.ts
- Remove OmoGlobalConfig type and merge preview functions
- Remove useGlobalConfig/useSaveGlobalConfig query hooks
- Simplify useOmoDraftState (remove all common config state)
- Replace OmoCommonConfigEditor with read-only JsonEditor preview
- Clean i18n keys (zh/en/ja)

src-tauri/src/database/dao/mod.rs

@@ -4,7 +4,6 @@
 
 pub mod failover;
 pub mod mcp;
-pub mod omo;
 pub mod prompts;
 pub mod providers;
 pub mod proxy;
@@ -16,4 +15,3 @@ pub mod universal_providers;
 // 所有 DAO 方法都通过 Database impl 提供，无需单独导出
 // 导出 FailoverQueueItem 供外部使用
 pub use failover::FailoverQueueItem;
-pub use omo::OmoGlobalConfig;

src-tauri/src/database/dao/omo.rs

@@ -1,77 +0,0 @@
-use crate::database::Database;
-use crate::error::AppError;
-use serde::{Deserialize, Serialize};
-
-#[derive(Debug, Clone, Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-pub struct OmoGlobalConfig {
-    pub id: String,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub schema_url: Option<String>,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub sisyphus_agent: Option<serde_json::Value>,
-    #[serde(default)]
-    pub disabled_agents: Vec<String>,
-    #[serde(default)]
-    pub disabled_mcps: Vec<String>,
-    #[serde(default)]
-    pub disabled_hooks: Vec<String>,
-    #[serde(default)]
-    pub disabled_skills: Vec<String>,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub lsp: Option<serde_json::Value>,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub experimental: Option<serde_json::Value>,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub background_task: Option<serde_json::Value>,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub browser_automation_engine: Option<serde_json::Value>,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub claude_code: Option<serde_json::Value>,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub other_fields: Option<serde_json::Value>,
-    pub updated_at: String,
-}
-
-impl Default for OmoGlobalConfig {
-    fn default() -> Self {
-        Self {
-            id: "global".to_string(),
-            schema_url: None,
-            sisyphus_agent: None,
-            disabled_agents: vec![],
-            disabled_mcps: vec![],
-            disabled_hooks: vec![],
-            disabled_skills: vec![],
-            lsp: None,
-            experimental: None,
-            background_task: None,
-            browser_automation_engine: None,
-            claude_code: None,
-            other_fields: None,
-            updated_at: chrono::Utc::now().to_rfc3339(),
-        }
-    }
-}
-
-impl Database {
-    pub fn get_omo_global_config(&self, key: &str) -> Result<OmoGlobalConfig, AppError> {
-        let json_str = self.get_setting(key)?;
-        match json_str {
-            Some(s) => serde_json::from_str::<OmoGlobalConfig>(&s)
-                .map_err(|e| AppError::Config(format!("Failed to parse {key}: {e}"))),
-            None => Ok(OmoGlobalConfig::default()),
-        }
-    }
-
-    pub fn save_omo_global_config(
-        &self,
-        key: &str,
-        config: &OmoGlobalConfig,
-    ) -> Result<(), AppError> {
-        let json_str = serde_json::to_string(config)
-            .map_err(|e| AppError::Config(format!("JSON serialization failed: {e}")))?;
-        self.set_setting(key, &json_str)?;
-        Ok(())
-    }
-}

src-tauri/src/database/dao/settings.rs

@@ -38,31 +38,6 @@ impl Database {
         Ok(())
     }
 
-    // --- Config Snippets 辅助方法 ---
-
-    /// 获取通用配置片段
-    pub fn get_config_snippet(&self, app_type: &str) -> Result<Option<String>, AppError> {
-        self.get_setting(&format!("common_config_{app_type}"))
-    }
-
-    /// 设置通用配置片段
-    pub fn set_config_snippet(
-        &self,
-        app_type: &str,
-        snippet: Option<String>,
-    ) -> Result<(), AppError> {
-        let key = format!("common_config_{app_type}");
-        if let Some(value) = snippet {
-            self.set_setting(&key, &value)
-        } else {
-            // 如果为 None 则删除
-            let conn = lock_conn!(self.conn);
-            conn.execute("DELETE FROM settings WHERE key = ?1", params![key])
-                .map_err(|e| AppError::Database(e.to_string()))?;
-            Ok(())
-        }
-    }
-
     // --- 全局出站代理 ---
 
     /// 全局代理 URL 的存储键名

src-tauri/src/database/mod.rs

@@ -33,7 +33,6 @@ mod tests;
 
 // DAO 类型导出供外部使用
 pub use dao::FailoverQueueItem;
-pub use dao::OmoGlobalConfig;
 
 use crate::config::get_app_config_dir;
 use crate::error::AppError;