feat: add skill storage location toggle between CC Switch and ~/.agents/skills

Allow users to choose between storing skills in CC Switch's managed
directory (~/.cc-switch/skills/) or the Agent Skills open standard
directory (~/.agents/skills/). Includes migration logic that safely
moves files before updating settings, with confirmation dialog for
non-empty installations.

src/components/settings/SettingsPage.tsx

@@ -32,6 +32,7 @@ import { LanguageSettings } from "@/components/settings/LanguageSettings";
 import { ThemeSettings } from "@/components/settings/ThemeSettings";
 import { WindowSettings } from "@/components/settings/WindowSettings";
 import { AppVisibilitySettings } from "@/components/settings/AppVisibilitySettings";
+import { SkillStorageLocationSettings } from "@/components/settings/SkillStorageLocationSettings";
 import { SkillSyncMethodSettings } from "@/components/settings/SkillSyncMethodSettings";
 import { TerminalSettings } from "@/components/settings/TerminalSettings";
 import { DirectorySettings } from "@/components/settings/DirectorySettings";
@@ -44,6 +45,7 @@ import { ModelTestConfigPanel } from "@/components/usage/ModelTestConfigPanel";
 import { UsageDashboard } from "@/components/usage/UsageDashboard";
 import { LogConfigPanel } from "@/components/settings/LogConfigPanel";
 import { AuthCenterPanel } from "@/components/settings/AuthCenterPanel";
+import { useInstalledSkills } from "@/hooks/useSkills";
 import { useSettings } from "@/hooks/useSettings";
 import { useImportExport } from "@/hooks/useImportExport";
 import { useTranslation } from "react-i18next";
@@ -96,6 +98,8 @@ export function SettingsPage({
     resetStatus,
   } = useImportExport({ onImportSuccess });
 
+  const { data: installedSkills } = useInstalledSkills();
+
   const [activeTab, setActiveTab] = useState<string>("general");
   const [showRestartPrompt, setShowRestartPrompt] = useState(false);
 
@@ -229,6 +233,13 @@ export function SettingsPage({
                       settings={settings}
                       onChange={handleAutoSave}
                     />
+                    <SkillStorageLocationSettings
+                      value={settings.skillStorageLocation ?? "cc_switch"}
+                      installedCount={installedSkills?.length ?? 0}
+                      onMigrated={(location) =>
+                        updateSettings({ skillStorageLocation: location })
+                      }
+                    />
                     <SkillSyncMethodSettings
                       value={settings.skillSyncMethod ?? "auto"}
                       onChange={(method) =>