refactor(api): use predefined structs for fixed API responses

- Add api/types.go with predefined response struct types

- Replace map[string]any with typed structs for all fixed-content API endpoints

- Use predefined instances for Healthcheck and Version handlers to reduce allocations

- Improve performance by avoiding per-request map allocations

api/types.go

@@ -0,0 +1,84 @@
+package api
+
+// 预定义的固定响应内容，避免每次请求时创建 map
+
+// HealthcheckResponse 健康检查响应
+type HealthcheckResponse struct {
+	Status string `json:"Status"`
+	Repo   string `json:"Repo"`
+	Author string `json:"Author"`
+}
+
+// VersionResponse 版本信息响应
+type VersionResponse struct {
+	Version string `json:"Version"`
+	Repo    string `json:"Repo"`
+	Author  string `json:"Author"`
+}
+
+// BoolStatusResponse 布尔状态响应
+type BoolStatusResponse struct {
+	Enabled bool `json:"enabled"`
+}
+
+// SizeLimitResponse 大小限制响应
+type SizeLimitResponse struct {
+	MaxResponseBodySize int `json:"MaxResponseBodySize"`
+}
+
+// WhitelistStatusResponse 白名单状态响应
+type WhitelistStatusResponse struct {
+	Whitelist bool `json:"Whitelist"`
+}
+
+// BlacklistStatusResponse 黑名单状态响应
+type BlacklistStatusResponse struct {
+	Blacklist bool `json:"Blacklist"`
+}
+
+// CorsStatusResponse CORS 状态响应
+type CorsStatusResponse struct {
+	Cors string `json:"Cors"`
+}
+
+// RateLimitStatusResponse 速率限制状态响应
+type RateLimitStatusResponse struct {
+	RateLimit bool `json:"RateLimit"`
+}
+
+// RateLimitLimitResponse 速率限制值响应
+type RateLimitLimitResponse struct {
+	RatePerMinute int `json:"RatePerMinute"`
+}
+
+// SmartGitStatusResponse SmartGit 状态响应
+type SmartGitStatusResponse struct {
+	Enabled bool `json:"enabled"`
+}
+
+// ShellNestStatusResponse Shell Nest 状态响应
+type ShellNestStatusResponse struct {
+	Enabled bool `json:"enabled"`
+}
+
+// OCIDockerResponse OCI/Docker 代理状态响应
+type OCIDockerResponse struct {
+	Enabled bool   `json:"enabled"`
+	Target  string `json:"target,omitempty"`
+}
+
+// 预定义的固定响应实例，避免重复分配
+var (
+	// baseHealthcheckResponse 基础健康检查响应（固定部分）
+	baseHealthcheckResponse = HealthcheckResponse{
+		Status: "OK",
+		Repo:   "WJQSERVER-STUDIO/GHProxy",
+		Author: "WJQSERVER-STUDIO",
+	}
+
+	// baseVersionResponse 基础版本响应（固定部分）
+	baseVersionResponse = VersionResponse{
+		Repo:   "WJQSERVER-STUDIO/GHProxy",
+		Author: "WJQSERVER-STUDIO",
+	}
+)