优化结构

internal/config/clone.go

@@ -10,3 +10,44 @@ func CloneAdmin(value *Admin) *Admin          { return cloneAdmin(value) }
 func CloneDatabase(value *Database) *Database { return clonePtr(value) }
 func CloneStorage(value *Storage) *Storage    { return cloneStorage(value) }
 func CloneEmail(value *Email) *Email          { return clonePtr(value) }
+
+// MergeRuntimeConfig applies the runtime replacement contract shared by file
+// watching and management updates. Omitted top-level sections keep their
+// current values, while database-backed storage/email settings are never
+// erased merely because they are absent from config.yaml.
+func MergeRuntimeConfig(current, next *Config) *Config {
+	merged := cloneConfig(next)
+	if merged == nil {
+		merged = &Config{}
+	}
+	if current == nil {
+		if merged.Admin == nil {
+			merged.Admin = &Admin{}
+		}
+		return merged
+	}
+	if merged.Server == nil {
+		merged.Server = clonePtr(current.Server)
+	}
+	if merged.Data == nil {
+		merged.Data = cloneData(current.Data)
+	}
+	if merged.Admin == nil {
+		merged.Admin = cloneAdmin(current.Admin)
+	}
+	if merged.Admin == nil {
+		merged.Admin = &Admin{}
+	}
+	if current.Admin != nil {
+		if merged.Admin.Storage == nil {
+			merged.Admin.Storage = cloneStorage(current.Admin.Storage)
+		}
+		if merged.Admin.Email == nil {
+			merged.Admin.Email = clonePtr(current.Admin.Email)
+		}
+		if merged.Admin.ConfigPath == "" {
+			merged.Admin.ConfigPath = current.Admin.ConfigPath
+		}
+	}
+	return merged
+}