feat: complete remaining Go backend modules

contracts/admin/http-auth-compat-v1.json

@@ -0,0 +1,8 @@
+{
+  "version": 1,
+  "routes": [
+    { "method": "GET", "path": "/api/auth/login", "status": 307, "location": "/auth/login" },
+    { "method": "GET", "path": "/api/auth/callback", "status": 307, "location": "/auth/login?error=callback_failed" },
+    { "method": "GET", "path": "/api/auth/captcha", "status": 200, "body": { "enabled": false, "message": "平台账号登录不使用外部验证码。" } }
+  ]
+}

contracts/admin/http-v1.json

@@ -0,0 +1,12 @@
+{
+  "version": 1,
+  "routes": [
+    { "path": "/api/admin/accounts", "methods": ["GET", "POST", "PATCH", "PUT", "DELETE"], "requirement": "admin" },
+    { "path": "/api/admin/accounts/password", "methods": ["POST"], "requirement": "admin" },
+    { "path": "/api/admin/organizations", "methods": ["GET", "POST", "PATCH", "DELETE"], "requirement": "admin" },
+    { "path": "/api/admin/accounts/groups", "methods": ["POST"], "requirement": "public-compatibility", "status": 410 }
+  ],
+  "accountProjection": ["id", "phone", "displayName", "role", "organizationId", "status", "createdAt", "lastLoginAt", "lockedUntil"],
+  "organizationProjection": ["id", "name", "status"],
+  "secretFields": ["passwordHash", "passwordSalt", "failedLoginCount", "sessionVersion", "legacySubject"]
+}