feat(skills): unified management architecture with SSOT and React Query

- Introduce SSOT (Single Source of Truth) at ~/.cc-switch/skills/
- Add three-app toggle support (Claude/Codex/Gemini) for each skill
- Refactor frontend to use TanStack Query hooks instead of manual state
- Add UnifiedSkillsPanel for managing installed skills with app toggles
- Add useSkills.ts with declarative data fetching hooks
- Extend skills.ts API with unified install/uninstall/toggle methods
- Support importing unmanaged skills from app directories
- Add v2→v3 database migration for new skills table structure

src/hooks/useSkills.ts

@@ -0,0 +1,151 @@
+import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
+import {
+  skillsApi,
+  type AppType,
+  type DiscoverableSkill,
+  type InstalledSkill,
+} from "@/lib/api/skills";
+
+/**
+ * 查询所有已安装的 Skills
+ */
+export function useInstalledSkills() {
+  return useQuery({
+    queryKey: ["skills", "installed"],
+    queryFn: () => skillsApi.getInstalled(),
+  });
+}
+
+/**
+ * 发现可安装的 Skills（从仓库获取）
+ */
+export function useDiscoverableSkills() {
+  return useQuery({
+    queryKey: ["skills", "discoverable"],
+    queryFn: () => skillsApi.discoverAvailable(),
+    staleTime: 5 * 60 * 1000, // 5 分钟内不重新获取
+  });
+}
+
+/**
+ * 安装 Skill
+ */
+export function useInstallSkill() {
+  const queryClient = useQueryClient();
+  return useMutation({
+    mutationFn: ({
+      skill,
+      currentApp,
+    }: {
+      skill: DiscoverableSkill;
+      currentApp: AppType;
+    }) => skillsApi.installUnified(skill, currentApp),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ["skills", "installed"] });
+      queryClient.invalidateQueries({ queryKey: ["skills", "discoverable"] });
+    },
+  });
+}
+
+/**
+ * 卸载 Skill
+ */
+export function useUninstallSkill() {
+  const queryClient = useQueryClient();
+  return useMutation({
+    mutationFn: (id: string) => skillsApi.uninstallUnified(id),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ["skills", "installed"] });
+      queryClient.invalidateQueries({ queryKey: ["skills", "discoverable"] });
+    },
+  });
+}
+
+/**
+ * 切换 Skill 在特定应用的启用状态
+ */
+export function useToggleSkillApp() {
+  const queryClient = useQueryClient();
+  return useMutation({
+    mutationFn: ({
+      id,
+      app,
+      enabled,
+    }: {
+      id: string;
+      app: AppType;
+      enabled: boolean;
+    }) => skillsApi.toggleApp(id, app, enabled),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ["skills", "installed"] });
+    },
+  });
+}
+
+/**
+ * 扫描未管理的 Skills
+ */
+export function useScanUnmanagedSkills() {
+  return useQuery({
+    queryKey: ["skills", "unmanaged"],
+    queryFn: () => skillsApi.scanUnmanaged(),
+    enabled: false, // 手动触发
+  });
+}
+
+/**
+ * 从应用目录导入 Skills
+ */
+export function useImportSkillsFromApps() {
+  const queryClient = useQueryClient();
+  return useMutation({
+    mutationFn: (directories: string[]) => skillsApi.importFromApps(directories),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ["skills", "installed"] });
+      queryClient.invalidateQueries({ queryKey: ["skills", "unmanaged"] });
+    },
+  });
+}
+
+/**
+ * 获取仓库列表
+ */
+export function useSkillRepos() {
+  return useQuery({
+    queryKey: ["skills", "repos"],
+    queryFn: () => skillsApi.getRepos(),
+  });
+}
+
+/**
+ * 添加仓库
+ */
+export function useAddSkillRepo() {
+  const queryClient = useQueryClient();
+  return useMutation({
+    mutationFn: skillsApi.addRepo,
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ["skills", "repos"] });
+      queryClient.invalidateQueries({ queryKey: ["skills", "discoverable"] });
+    },
+  });
+}
+
+/**
+ * 删除仓库
+ */
+export function useRemoveSkillRepo() {
+  const queryClient = useQueryClient();
+  return useMutation({
+    mutationFn: ({ owner, name }: { owner: string; name: string }) =>
+      skillsApi.removeRepo(owner, name),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ["skills", "repos"] });
+      queryClient.invalidateQueries({ queryKey: ["skills", "discoverable"] });
+    },
+  });
+}
+
+// ========== 辅助类型 ==========
+
+export type { InstalledSkill, DiscoverableSkill, AppType };