M4: harness + green install stage (custom-html + Playwright); guaranteed teardown; M4 CLAIMED

run_recipe_ci.py + conftest + abra/lifecycle wrappers + Nix python/playwright env.
deploy_app forces LETS_ENCRYPT_ENV='' (addresses A1). Short per-run domain scheme
for the 64-char swarm name limit. 2 passed; teardown leaves zero orphans.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/custom-html/test_install.py

@@ -0,0 +1,30 @@
+"""custom-html — install stage (recipe #1, simple/stateless). D2 install + D3 Playwright."""
+import sys
+import os
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "..", "runner"))
+from harness import lifecycle  # noqa: E402
+
+
+def test_http_reachable(deployed_app):
+    """The deployed app answers 200 over real HTTPS through the gateway."""
+    status = lifecycle.http_get(deployed_app, "/")
+    assert status == 200, f"expected 200 from {deployed_app}, got {status}"
+
+
+def test_playwright_page(deployed_app):
+    """A real browser (Playwright/Chromium) loads the live app and sees served content."""
+    from playwright.sync_api import sync_playwright
+
+    url = f"https://{deployed_app}/"
+    with sync_playwright() as p:
+        browser = p.chromium.launch(args=["--no-sandbox"])
+        try:
+            ctx = browser.new_context(ignore_https_errors=True)
+            page = ctx.new_page()
+            resp = page.goto(url, wait_until="load", timeout=30000)
+            assert resp is not None and resp.status == 200, f"page status {resp and resp.status}"
+            body = page.content()
+            assert "nginx" in body.lower() or "<html" in body.lower(), "no served HTML content"
+        finally:
+            browser.close()