Add admin panel, WebSocket support, and API versioning

Introduce an admin portal (React + Nginx), WebSocket routing, and
API versioning middleware with `/api/v1/` prefix deprecation.
Add master API key authentication, new Prometheus metrics for AI
token consumption and active WebSockets, and extend S3 config
with a public endpoint URL. Update test paths and fixtures to
align with the new routing structure.

imago-admin/vitest.config.ts

@@ -0,0 +1,20 @@
+/// <reference types="vitest" />
+import { defineConfig } from 'vite';
+import react from '@vitejs/plugin-react';
+import path from 'path';
+
+export default defineConfig({
+    plugins: [react()],
+    test: {
+        globals: true,
+        environment: 'jsdom',
+        setupFiles: ['./src/test/setup.ts'],
+        include: ['src/**/*.test.{ts,tsx}'],
+        css: false,
+    },
+    resolve: {
+        alias: {
+            '@': path.resolve(__dirname, './src'),
+        },
+    },
+});