test(admin): Playwright chart tests — 11 scenarios, fully mocked

Covers axes, live label format, path update on delta, 1 s poll cadence,
rate decay after CHART_TICK, burst overflow clamp, and header elements.
All network I/O mocked via page.route(); no live Quarkus server required.

Co-Authored-By: Mira Rehfeld <noreply@anthropic.com>

apix-admin/playwright.config.js

@@ -0,0 +1,14 @@
+// @ts-check
+const { defineConfig } = require('@playwright/test');
+
+module.exports = defineConfig({
+  testDir: './tests',
+  timeout: 30_000,
+  retries: 0,
+  reporter: [['line'], ['html', { open: 'never' }]],
+  use: {
+    baseURL: process.env.APIX_ADMIN_URL || 'http://localhost:8084',
+    // Cookie set by the auth filter; value must match APIX_API_KEY on the registry
+    storageState: undefined,
+  },
+});