feat: add credential-safe multiplayer observability

server/observability/log_test.go

@@ -0,0 +1,32 @@
+package observability
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+)
+
+func TestEncodeCorrelatesStagesAndRedactsNestedCredentials(t *testing.T) {
+	payload, err := Encode(Event{Event: "assignment_ready", QueueID: "queue-1", ProposalID: "proposal-1", MatchID: "match-1", ServerID: "server-1", Stage: "assignment-ready", OccurredAt: time.Unix(1000, 0), Fields: map[string]any{"auth_ticket": "do-not-log", "nested": map[string]any{"relay_ticket": "also-secret", "attempt": 2}}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	var decoded map[string]any
+	if err := json.Unmarshal(payload, &decoded); err != nil {
+		t.Fatal(err)
+	}
+	for _, key := range []string{"queue_id", "proposal_id", "match_id", "server_id", "stage"} {
+		if decoded[key] == nil {
+			t.Fatalf("missing correlation field %q: %s", key, payload)
+		}
+	}
+	if decoded["auth_ticket"] != "[REDACTED]" || decoded["nested"].(map[string]any)["relay_ticket"] != "[REDACTED]" {
+		t.Fatalf("credential not redacted: %s", payload)
+	}
+}
+
+func TestEncodeRejectsUnnamedEvents(t *testing.T) {
+	if _, err := Encode(Event{}); err == nil {
+		t.Fatal("unnamed event accepted")
+	}
+}