fix(validators): make username/password optional in HTTP/HTTPS node validators

Align with mihomo specification where both username and password are optional
fields (marked as omitempty). This allows HTTP proxies without authentication.

Fixes #321 (part 1/2)

Author: geekdada

src/validators/http.ts

@@ -12,16 +12,16 @@ export const HttpNodeConfigValidator = SimpleNodeConfigValidator.extend({
   type: z.literal(NodeTypeEnum.HTTP),
   hostname: z.string(),
   port: PortValidator,
-  username: z.string(),
-  password: z.string(),
+  username: z.string().optional(),
+  password: z.string().optional(),
   path: z.string().optional(),
   headers: z.record(z.string()).optional(),
 })
 
 export const HttpsNodeConfigValidator = TlsNodeConfigValidator.extend({
   type: z.literal(NodeTypeEnum.HTTPS),
-  username: z.string(),
-  password: z.string(),
+  username: z.string().optional(),
+  password: z.string().optional(),
   path: z.string().optional(),
   headers: z.record(z.string()).optional(),
 })