refactor: cleanup and minor improvements

- Remove unused useDarkMode hook (now using shadcn theme-provider)
- Clean up MCP components (remove redundant code)
- Add restart API to settings
- Minor type improvements

src/components/mcp/McpFormModal.tsx

@@ -18,21 +18,11 @@ import {
 import { Input } from "@/components/ui/input";
 import { Textarea } from "@/components/ui/textarea";
 import { mcpApi, type AppType } from "@/lib/api";
-import { McpServer, McpServerSpec } from "../../types";
-import {
-  mcpPresets,
-  getMcpPresetWithDescription,
-} from "../../config/mcpPresets";
+import { McpServer, McpServerSpec } from "@/types";
+import { mcpPresets, getMcpPresetWithDescription } from "@/config/mcpPresets";
 import McpWizardModal from "./McpWizardModal";
-import {
-  extractErrorMessage,
-  translateMcpBackendError,
-} from "../../utils/errorUtils";
-import {
-  tomlToMcpServer,
-  extractIdFromToml,
-  mcpServerToToml,
-} from "../../utils/tomlUtils";
+import { extractErrorMessage, translateMcpBackendError } from "@/utils/errorUtils";
+import { tomlToMcpServer, extractIdFromToml, mcpServerToToml } from "@/utils/tomlUtils";
 import { useMcpValidation } from "./useMcpValidation";
 
 interface McpFormModalProps {

src/components/mcp/McpListItem.tsx

@@ -3,8 +3,8 @@ import { useTranslation } from "react-i18next";
 import { Edit3, Trash2 } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { settingsApi } from "@/lib/api";
-import { McpServer } from "../../types";
-import { mcpPresets } from "../../config/mcpPresets";
+import { McpServer } from "@/types";
+import { mcpPresets } from "@/config/mcpPresets";
 import McpToggle from "./McpToggle";
 
 interface McpListItemProps {

src/components/mcp/McpPanel.tsx

@@ -9,14 +9,11 @@ import {
   DialogTitle,
 } from "@/components/ui/dialog";
 import { mcpApi, type AppType } from "@/lib/api";
-import { McpServer } from "../../types";
+import { McpServer } from "@/types";
 import McpListItem from "./McpListItem";
 import McpFormModal from "./McpFormModal";
 import { ConfirmDialog } from "../ConfirmDialog";
-import {
-  extractErrorMessage,
-  translateMcpBackendError,
-} from "../../utils/errorUtils";
+import { extractErrorMessage, translateMcpBackendError } from "@/utils/errorUtils";
 
 interface McpPanelProps {
   open: boolean;

src/components/mcp/McpWizardModal.tsx

@@ -9,7 +9,7 @@ import {
   DialogTitle,
   DialogFooter,
 } from "@/components/ui/dialog";
-import { McpServerSpec } from "../../types";
+import { McpServerSpec } from "@/types";
 
 interface McpWizardModalProps {
   isOpen: boolean;