fix(ci): wait for final B5 database readiness

apps/api/tests/test_cd_b5_database_readiness_gate.py

@@ -0,0 +1,18 @@
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[3]
+CD_WORKFLOW = ROOT / ".gitea" / "workflows" / "cd.yaml"
+
+
+def test_b5_waits_for_final_postmaster_and_same_network_client() -> None:
+    workflow = CD_WORKFLOW.read_text(encoding="utf-8")
+    b5 = workflow.split("- name: Integration Tests (B5 — 真實 DB)", 1)[1]
+    b5 = b5.split("- name: Clean Test Workspace Artifacts", 1)[0]
+
+    assert "PostgreSQL init process complete; ready for start up." in b5
+    assert 'B5_CLIENT_READY=0' in b5
+    assert "-v ON_ERROR_STOP=1 -Atqc 'SELECT 1'" in b5
+    assert "b5_pg_test_client_network_not_ready" in b5
+    assert "inspect_b5_final_postmaster_and_test_network_then_retry_cd" in b5
+    assert b5.index("B5_CLIENT_READY=0") < b5.index("setup_test_schema.sql")