refactor(auth): remove keys auth module and align tests

- remove server auth module and client keys page/routes/api to simplify flow

- update mcp and scenario tests to match uuid routes and step schema

client/src/api/client.ts

@@ -2,7 +2,6 @@ import type {
   PaginatedResponse,
   Credential,
   Environment,
-  KeysResponse,
   ScenarioCredential,
   Session,
   Scenario,
@@ -13,7 +12,7 @@ import type {
   Snippet,
 } from './types';
 
-// In dev, Vite proxies /environments /sessions /scenarios /keys to localhost:3000.
+// In dev, Vite proxies /environments /sessions /scenarios to localhost:3000.
 // In production (or when VITE_API_URL is set) we hit the configured origin directly.
 const BASE_URL: string = (import.meta.env.VITE_API_URL as string | undefined) ?? '';
 
@@ -132,14 +131,6 @@ export const environments = {
   },
 };
 
-// ── Keys ──────────────────────────────────────────────────────────────────────
-
-export const keys = {
-  list(): Promise<KeysResponse> {
-    return request('/keys');
-  },
-};
-
 // ── Sessions ──────────────────────────────────────────────────────────────────
 
 export const sessions = {

client/src/api/types.ts

@@ -46,12 +46,6 @@ export interface Snippet {
   updatedAt: string;
 }
 
-// ── Keys ──────────────────────────────────────────────────────────────────────
-
-export interface KeysResponse {
-  keys: string[];
-}
-
 // ── Sessions ──────────────────────────────────────────────────────────────────
 
 export type SessionStatus = 'open' | 'closed';