chore: add diagnostic logging for circuit breaker upgrade test CI failure

The test passes locally but fails consistently on CI with "Internal server
error". Diagnostics confirmed the circuit breaker works correctly
(employeesCalls=4, status changed=2), so the issue is in the WebSocket
communication layer after the HTTP 101 upgrade succeeds. Adding WARN/ERROR
log capture to identify the exact subscription resolution error on CI.

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

Author: SkArchon

router-tests/security/circuit_breaker_test.go

@@ -753,6 +753,14 @@ func TestCircuitBreaker(t *testing.T) {
 			t.Logf("received message: %s", string(message))
 			t.Logf("circuit breaker status changed count: %d", xEnv.Observer().FilterMessage("Circuit breaker status changed").Len())
 			t.Logf("circuit breaker open count: %d", xEnv.Observer().FilterMessage("Circuit breaker open, request callback did not execute").Len())
+			for _, entry := range xEnv.Observer().FilterMessage("Resolving GraphQL subscription").All() {
+				t.Logf("subscription resolve error: %v", entry.ContextMap())
+			}
+			for _, entry := range xEnv.Observer().All() {
+				if entry.Level >= zapcore.WarnLevel {
+					t.Logf("WARN/ERROR log: %s | %v", entry.Message, entry.ContextMap())
+				}
+			}
 
 			require.JSONEq(t, timestampMessage, string(message))