revert: restore full config overwrite + Common Config Snippet (revert 992dda5c)

Revert the partial key-field merging refactoring introduced in 992dda5c,
along with two dependent commits (24fa8a18, 87604b18) that referenced
the now-removed ClaudeQuickToggles component.

The whitelist-based partial merge approach had critical issues:
- Non-whitelisted custom fields were lost during provider switching
- Backfill permanently stripped non-key fields from the database
- Whitelist required constant maintenance to track upstream changes

This restores the proven "full config overwrite + Common Config Snippet"
architecture where each provider stores its complete configuration and
shared settings are managed via a separate snippet mechanism.

Reverted commits:
- 24fa8a18: context-aware JSON editor hint + hide quick toggles
- 87604b18: hide ClaudeQuickToggles when creating
- 992dda5c: partial key-field merging refactoring

Restored:
- Full config snapshot write (write_live_snapshot) for Claude/Codex/Gemini
- Full config backfill (settings_config = live_config)
- Common Config Snippet UI and backend commands
- 6 frontend components/hooks for common config editing
- configApi barrel export and DB snippet methods

Removed:
- ClaudeQuickToggles component
- write_live_partial / backfill_key_fields / patch_claude_live
- All KEY_FIELDS constants

src-tauri/src/commands/config.rs

@@ -7,6 +7,7 @@ use tauri_plugin_opener::OpenerExt;
 use crate::app_config::AppType;
 use crate::codex_config;
 use crate::config::{self, get_claude_settings_path, ConfigStatus};
+use crate::settings;
 
 #[tauri::command]
 pub async fn get_claude_config_status() -> Result<ConfigStatus, String> {
@@ -15,6 +16,18 @@ pub async fn get_claude_config_status() -> Result<ConfigStatus, String> {
 
 use std::str::FromStr;
 
+fn invalid_json_format_error(error: serde_json::Error) -> String {
+    let lang = settings::get_settings()
+        .language
+        .unwrap_or_else(|| "zh".to_string());
+
+    match lang.as_str() {
+        "en" => format!("Invalid JSON format: {error}"),
+        "ja" => format!("JSON形式が無効です: {error}"),
+        _ => format!("无效的 JSON 格式: {error}"),
+    }
+}
+
 #[tauri::command]
 pub async fn get_config_status(app: String) -> Result<ConfigStatus, String> {
     match AppType::from_str(&app).map_err(|e| e.to_string())? {
@@ -150,3 +163,126 @@ pub async fn open_app_config_folder(handle: AppHandle) -> Result<bool, String> {
 
     Ok(true)
 }
+
+#[tauri::command]
+pub async fn get_claude_common_config_snippet(
+    state: tauri::State<'_, crate::store::AppState>,
+) -> Result<Option<String>, String> {
+    state
+        .db
+        .get_config_snippet("claude")
+        .map_err(|e| e.to_string())
+}
+
+#[tauri::command]
+pub async fn set_claude_common_config_snippet(
+    snippet: String,
+    state: tauri::State<'_, crate::store::AppState>,
+) -> Result<(), String> {
+    if !snippet.trim().is_empty() {
+        serde_json::from_str::<serde_json::Value>(&snippet).map_err(invalid_json_format_error)?;
+    }
+
+    let value = if snippet.trim().is_empty() {
+        None
+    } else {
+        Some(snippet)
+    };
+
+    state
+        .db
+        .set_config_snippet("claude", value)
+        .map_err(|e| e.to_string())?;
+    Ok(())
+}
+
+#[tauri::command]
+pub async fn get_common_config_snippet(
+    app_type: String,
+    state: tauri::State<'_, crate::store::AppState>,
+) -> Result<Option<String>, String> {
+    state
+        .db
+        .get_config_snippet(&app_type)
+        .map_err(|e| e.to_string())
+}
+
+#[tauri::command]
+pub async fn set_common_config_snippet(
+    app_type: String,
+    snippet: String,
+    state: tauri::State<'_, crate::store::AppState>,
+) -> Result<(), String> {
+    if !snippet.trim().is_empty() {
+        match app_type.as_str() {
+            "claude" | "gemini" | "omo" | "omo-slim" => {
+                serde_json::from_str::<serde_json::Value>(&snippet)
+                    .map_err(invalid_json_format_error)?;
+            }
+            "codex" => {}
+            _ => {}
+        }
+    }
+
+    let value = if snippet.trim().is_empty() {
+        None
+    } else {
+        Some(snippet)
+    };
+
+    state
+        .db
+        .set_config_snippet(&app_type, value)
+        .map_err(|e| e.to_string())?;
+
+    if app_type == "omo"
+        && state
+            .db
+            .get_current_omo_provider("opencode", "omo")
+            .map_err(|e| e.to_string())?
+            .is_some()
+    {
+        crate::services::OmoService::write_config_to_file(
+            state.inner(),
+            &crate::services::omo::STANDARD,
+        )
+        .map_err(|e| e.to_string())?;
+    }
+    if app_type == "omo-slim"
+        && state
+            .db
+            .get_current_omo_provider("opencode", "omo-slim")
+            .map_err(|e| e.to_string())?
+            .is_some()
+    {
+        crate::services::OmoService::write_config_to_file(
+            state.inner(),
+            &crate::services::omo::SLIM,
+        )
+        .map_err(|e| e.to_string())?;
+    }
+    Ok(())
+}
+
+#[tauri::command]
+pub async fn extract_common_config_snippet(
+    appType: String,
+    settingsConfig: Option<String>,
+    state: tauri::State<'_, crate::store::AppState>,
+) -> Result<String, String> {
+    let app = AppType::from_str(&appType).map_err(|e| e.to_string())?;
+
+    if let Some(settings_config) = settingsConfig.filter(|s| !s.trim().is_empty()) {
+        let settings: serde_json::Value =
+            serde_json::from_str(&settings_config).map_err(invalid_json_format_error)?;
+
+        return crate::services::provider::ProviderService::extract_common_config_snippet_from_settings(
+            app,
+            &settings,
+        )
+        .map_err(|e| e.to_string());
+    }
+
+    crate::services::provider::ProviderService::extract_common_config_snippet(&state, app)
+        .map_err(|e| e.to_string())
+}

src-tauri/src/commands/provider.rs

@@ -97,7 +97,27 @@ pub fn switch_provider(
 }
 
 fn import_default_config_internal(state: &AppState, app_type: AppType) -> Result<bool, AppError> {
-    let imported = ProviderService::import_default_config(state, app_type)?;
+    let imported = ProviderService::import_default_config(state, app_type.clone())?;
+
+    if imported {
+        // Extract common config snippet (mirrors old startup logic in lib.rs)
+        if state
+            .db
+            .get_config_snippet(app_type.as_str())
+            .ok()
+            .flatten()
+            .is_none()
+        {
+            match ProviderService::extract_common_config_snippet(state, app_type.clone()) {
+                Ok(snippet) if !snippet.is_empty() && snippet != "{}" => {
+                    let _ = state
+                        .db
+                        .set_config_snippet(app_type.as_str(), Some(snippet));
+                }
+                _ => {}
+            }
+        }
+    }
 
     Ok(imported)
 }
@@ -167,12 +187,6 @@ pub fn read_live_provider_settings(app: String) -> Result<serde_json::Value, Str
     ProviderService::read_live_settings(app_type).map_err(|e| e.to_string())
 }
 
-#[tauri::command]
-pub fn patch_claude_live_settings(patch: serde_json::Value) -> Result<bool, String> {
-    ProviderService::patch_claude_live(patch).map_err(|e| e.to_string())?;
-    Ok(true)
-}
-
 #[tauri::command]
 pub async fn test_api_endpoints(
     urls: Vec<String>,