refactor: reorganize test suite, add integration tests for NAT filter

- Move integration tests (api, network, phase2, smoke) to tests/integration/
- Move Playwright specs (captive-portal, interop-happy-path) to tests/e2e/
- Move playwright.config.mjs to tests/e2e/
- Fix hardcoded IP fallbacks: 192.168.4.1 → 10.192.45.1
- Add test-reset-auth.mjs: reset→pay→allow→revoke→block cycle
- Add test-session-expiry.mjs: pay→wait 65s→verify blocked (slow test)
- Add test-dns-firewall.mjs: DNS hijack/forward + per-client NAT filter
- Update Makefile with test-unit, test-integration, test-e2e, test-all targets
- Update package.json scripts for new paths
- Fix Playwright video: retain-on-failure instead of always-on
- Update AGENTS.md: per-client NAT filter description
- Update CHECKLIST.md: mark completed items, add Board B identity
- Board B nsec: 9af47906... → SSID TollGate-b96d80, AP IP 10.185.47.1
- 186 unit tests passing

1 files changed, 18 insertions, 0 deletions

diff --git a/tests/e2e/playwright.config.mjs b/tests/e2e/playwright.config.mjs
new file mode 100644
index 0000000..f4cbe01
--- /dev/null
+++ b/tests/e2e/playwright.config.mjs
@@ -0,0 +1,18 @@
+import { defineConfig } from '@playwright/test';
+
+export default defineConfig({
+  testDir: '.',
+  testMatch: '*.spec.mjs',
+  timeout: 120000,
+  retries: 0,
+  use: {
+    headless: true,
+    viewport: { width: 1280, height: 900 },
+    screenshot: 'on',
+    video: 'retain-on-failure',
+    trace: 'on-first-retry',
+  },
+  reporter: [['list'], ['html', { open: 'never' }]],
+  outputDir: 'test-results',
+  workers: 1,
+});