fix: align CI tests with current UI text and database naming

Backend conftest.py was hardcoded to patherly_test but CI creates
resolutionflow_test — now reads DATABASE_URL env var first. E2E tests
had stale placeholder text, heading, and landing page assertions.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/tests/conftest.py

@@ -24,8 +24,11 @@ settings.REQUIRE_INVITE_CODE = False
 # otherwise fall back to localhost for local development.
 import os
 TEST_DATABASE_URL = os.environ.get(
-    "DATABASE_TEST_URL",
-    "postgresql+asyncpg://postgres:postgres@localhost:5432/patherly_test",
+    "DATABASE_URL",
+    os.environ.get(
+        "DATABASE_TEST_URL",
+        "postgresql+asyncpg://postgres:postgres@localhost:5432/patherly_test",
+    ),
 )