fix(ingest): preserve valid RFC3339 packet timestamps

internal/ingest/packet.go

@@ -735,20 +735,11 @@ func (w *Worker) handlePacket(ctx context.Context, iata, pubkeyHex string, raw [
 		w.log.Error(fmt.Sprintf("db: upsert packet failed from %s/%s", iata, pubkeyHex), "error", err)
 		return
 	}
-	// Try parsing with timezone offset first
-	heardAt, err := time.Parse("2006-01-02T15:04:05.000000-07:00", envelope.Timestamp)
-	if err != nil {
-		heardAt, err = time.Parse("2006-01-02T15:04:05.000000", envelope.Timestamp)
-	}
-	if err != nil {
-		heardAt, err = time.Parse("2006-01-02T15:04:05.000000Z", envelope.Timestamp)
-	}
+	// Prefer an explicit RFC3339 offset; legacy timezone-less observers use UTC.
+	heardAt, err := time.Parse(time.RFC3339Nano, envelope.Timestamp)
 	if err != nil {
 		heardAt, err = time.Parse("2006-01-02T15:04:05", envelope.Timestamp)
 	}
-	if err != nil {
-		heardAt, err = time.Parse("2006-01-02T15:04:05Z", envelope.Timestamp)
-	}
 	if err != nil {
 		w.log.Warn(fmt.Sprintf("failed to parse timestamp %q", envelope.Timestamp), "error", err)
 		heardAt = time.Now().UTC()

internal/ingest/timestamp_test.go

@@ -0,0 +1,64 @@
+// Copyright 2026 Beacon Contributors
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+package ingest
+
+import (
+	"context"
+	"encoding/json"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestPacketTimestampFormatsAndSkew(t *testing.T) {
+	want := time.Now().UTC().Add(-10 * time.Minute).Truncate(time.Second).Add(123456789 * time.Nanosecond)
+	capture := func(t *testing.T, timestamp string) time.Time {
+		t.Helper()
+		w, base := newTestWorker()
+		db := &frameCaptureDB{stubDB: base}
+		w.db = db
+		var envelope map[string]string
+		if err := json.Unmarshal(packetEnvelope(t, buildGrpTxtPacket(t, 0x1a, make([]byte, 16))), &envelope); err != nil {
+			t.Fatal(err)
+		}
+		envelope["timestamp"] = timestamp
+		body, err := json.Marshal(envelope)
+		if err != nil {
+			t.Fatal(err)
+		}
+		w.handlePacket(context.Background(), "YOW", strings.Repeat("01", 32), body)
+		if len(db.observed) != 1 {
+			t.Fatal("timestamp prevented packet storage")
+		}
+		return db.observed[0].HeardAt
+	}
+	for _, zone := range []*time.Location{time.UTC, time.FixedZone("zero", 0), time.FixedZone("west", -4*60*60), time.FixedZone("east", 19800)} {
+		for _, precision := range []time.Duration{time.Second, time.Millisecond, time.Microsecond, time.Nanosecond} {
+			expected := want.Truncate(precision)
+			stamp := expected.In(zone).Format("2006-01-02T15:04:05.999999999-07:00")
+			if zone == time.UTC {
+				stamp = expected.Format(time.RFC3339Nano)
+			}
+			t.Run(stamp, func(t *testing.T) {
+				if got := capture(t, stamp); !got.Equal(expected) {
+					t.Fatalf("reported time changed: got %s want %s", got, expected)
+				}
+			})
+		}
+	}
+	for _, precision := range []time.Duration{time.Second, time.Microsecond, time.Nanosecond} {
+		expected := want.Truncate(precision)
+		stamp := expected.Format("2006-01-02T15:04:05.999999999")
+		if got := capture(t, stamp); !got.Equal(expected) {
+			t.Fatalf("timezone-less UTC changed: got %s want %s", got, expected)
+		}
+	}
+	for _, stamp := range []string{"", "invalid", "2026-09-29T25:00:00+00:00", time.Now().Add(31 * time.Minute).Format(time.RFC3339), time.Now().Add(-31 * time.Minute).Format(time.RFC3339)} {
+		before := time.Now().UTC()
+		got := capture(t, stamp)
+		if got.Before(before) || got.After(time.Now().UTC()) {
+			t.Fatalf("invalid/skewed time escaped server-time guard: %s => %s", stamp, got)
+		}
+	}
+}