refactor(mcp): complete v3.7.0 cleanup - remove legacy code and warnings

This commit finalizes the v3.7.0 unified MCP architecture migration by
removing all deprecated code paths and eliminating compiler warnings.

Frontend Changes (~950 lines removed):
- Remove deprecated components: McpPanel, McpListItem, McpToggle
- Remove deprecated hook: useMcpActions
- Remove unused API methods: importFrom*, syncEnabledTo*, syncAllServers
- Simplify McpFormModal by removing dual-mode logic (unified/legacy)
- Remove syncOtherSide checkbox and conflict detection
- Clean up unused imports and state variables
- Delete associated test files

Backend Changes (~400 lines cleaned):
- Remove unused Tauri commands: import_mcp_from_*, sync_enabled_mcp_to_*
- Delete unused Gemini MCP functions: get_mcp_status, upsert/delete_mcp_server
- Add #[allow(deprecated)] to compatibility layer commands
- Add #[allow(dead_code)] to legacy helper functions for future migration
- Simplify boolean expression in mcp.rs per Clippy suggestion

API Deprecation:
- Mark legacy APIs with @deprecated JSDoc (getConfig, upsertServerInConfig, etc.)
- Preserve backward compatibility for v3.x, planned removal in v4.0

Verification:
- ✅ Zero TypeScript errors (pnpm typecheck)
- ✅ Zero Clippy warnings (cargo clippy)
- ✅ All code formatted (prettier + cargo fmt)
- ✅ Builds successfully

Total cleanup: ~1,350 lines of code removed/marked
Breaking changes: None (all legacy APIs still functional)

src/hooks/useMcp.ts

@@ -1,14 +1,14 @@
-import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
-import { mcpApi } from '@/lib/api/mcp';
-import type { McpServer } from '@/types';
-import type { AppId } from '@/lib/api/types';
+import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
+import { mcpApi } from "@/lib/api/mcp";
+import type { McpServer } from "@/types";
+import type { AppId } from "@/lib/api/types";
 
 /**
  * 查询所有 MCP 服务器（统一管理）
  */
 export function useAllMcpServers() {
   return useQuery({
-    queryKey: ['mcp', 'all'],
+    queryKey: ["mcp", "all"],
     queryFn: () => mcpApi.getAllServers(),
   });
 }
@@ -21,7 +21,7 @@ export function useUpsertMcpServer() {
   return useMutation({
     mutationFn: (server: McpServer) => mcpApi.upsertUnifiedServer(server),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['mcp', 'all'] });
+      queryClient.invalidateQueries({ queryKey: ["mcp", "all"] });
     },
   });
 }
@@ -42,7 +42,7 @@ export function useToggleMcpApp() {
       enabled: boolean;
     }) => mcpApi.toggleApp(serverId, app, enabled),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['mcp', 'all'] });
+      queryClient.invalidateQueries({ queryKey: ["mcp", "all"] });
     },
   });
 }
@@ -55,7 +55,7 @@ export function useDeleteMcpServer() {
   return useMutation({
     mutationFn: (id: string) => mcpApi.deleteUnifiedServer(id),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['mcp', 'all'] });
+      queryClient.invalidateQueries({ queryKey: ["mcp", "all"] });
     },
   });
 }

src/hooks/useMcpActions.ts

@@ -1,136 +0,0 @@
-import { useCallback, useState } from "react";
-import { useTranslation } from "react-i18next";
-import { toast } from "sonner";
-import { mcpApi, type AppId } from "@/lib/api";
-import type { McpServer } from "@/types";
-import {
-  extractErrorMessage,
-  translateMcpBackendError,
-} from "@/utils/errorUtils";
-
-export interface UseMcpActionsResult {
-  servers: Record<string, McpServer>;
-  loading: boolean;
-  reload: () => Promise<void>;
-  toggleEnabled: (id: string, enabled: boolean) => Promise<void>;
-  saveServer: (
-    id: string,
-    server: McpServer,
-    options?: { syncOtherSide?: boolean },
-  ) => Promise<void>;
-  deleteServer: (id: string) => Promise<void>;
-}
-
-/**
- * useMcpActions - MCP management business logic
- * Responsibilities:
- * - Load MCP servers
- * - Toggle enable/disable status
- * - Save server configuration
- * - Delete server
- * - Error handling and toast notifications
- */
-export function useMcpActions(appId: AppId): UseMcpActionsResult {
-  const { t } = useTranslation();
-  const [servers, setServers] = useState<Record<string, McpServer>>({});
-  const [loading, setLoading] = useState(false);
-
-  const reload = useCallback(async () => {
-    setLoading(true);
-    try {
-      const cfg = await mcpApi.getConfig(appId);
-      setServers(cfg.servers || {});
-    } catch (error) {
-      console.error("[useMcpActions] Failed to load MCP config", error);
-      const detail = extractErrorMessage(error);
-      const mapped = translateMcpBackendError(detail, t);
-      toast.error(mapped || detail || t("mcp.error.loadFailed"), {
-        duration: mapped || detail ? 6000 : 5000,
-      });
-    } finally {
-      setLoading(false);
-    }
-  }, [appId, t]);
-
-  const toggleEnabled = useCallback(
-    async (id: string, enabled: boolean) => {
-      // Optimistic update
-      const previousServers = servers;
-      setServers((prev) => ({
-        ...prev,
-        [id]: {
-          ...prev[id],
-          enabled,
-        },
-      }));
-
-      try {
-        await mcpApi.setEnabled(appId, id, enabled);
-        toast.success(enabled ? t("mcp.msg.enabled") : t("mcp.msg.disabled"), {
-          duration: 1500,
-        });
-      } catch (error) {
-        // Rollback on failure
-        setServers(previousServers);
-        const detail = extractErrorMessage(error);
-        const mapped = translateMcpBackendError(detail, t);
-        toast.error(mapped || detail || t("mcp.error.saveFailed"), {
-          duration: mapped || detail ? 6000 : 5000,
-        });
-      }
-    },
-    [appId, servers, t],
-  );
-
-  const saveServer = useCallback(
-    async (
-      id: string,
-      server: McpServer,
-      options?: { syncOtherSide?: boolean },
-    ) => {
-      try {
-        const payload: McpServer = { ...server, id };
-        await mcpApi.upsertServerInConfig(appId, id, payload, {
-          syncOtherSide: options?.syncOtherSide,
-        });
-        await reload();
-        toast.success(t("mcp.msg.saved"), { duration: 1500 });
-      } catch (error) {
-        const detail = extractErrorMessage(error);
-        const mapped = translateMcpBackendError(detail, t);
-        const msg = mapped || detail || t("mcp.error.saveFailed");
-        toast.error(msg, { duration: mapped || detail ? 6000 : 5000 });
-        // Re-throw to allow form-level error handling
-        throw error;
-      }
-    },
-    [appId, reload, t],
-  );
-
-  const deleteServer = useCallback(
-    async (id: string) => {
-      try {
-        await mcpApi.deleteServerInConfig(appId, id);
-        await reload();
-        toast.success(t("mcp.msg.deleted"), { duration: 1500 });
-      } catch (error) {
-        const detail = extractErrorMessage(error);
-        const mapped = translateMcpBackendError(detail, t);
-        toast.error(mapped || detail || t("mcp.error.deleteFailed"), {
-          duration: mapped || detail ? 6000 : 5000,
-        });
-        throw error;
-      }
-    },
-    [appId, reload, t],
-  );
-
-  return {
-    servers,
-    loading,
-    reload,
-    toggleEnabled,
-    saveServer,
-    deleteServer,
-  };
-}