feat: sync ephemeral transient messages

Sync telesrv 570ccf8 (feat(ephemeral): implement Layer 228 transient messages).

Skipped telesrv docs changes per public sync rules; normalized the public appearance seed label.

internal/store/postgres/ephemeral_report_integration_test.go

@@ -0,0 +1,60 @@
+package postgres
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+	"time"
+
+	"telesrv/internal/domain"
+)
+
+func TestEphemeralReportStoreDurableEvidenceAndIdempotency(t *testing.T) {
+	pool := testPool(t)
+	ctx := context.Background()
+	now := time.Now()
+	reporter := now.UnixNano()&0x3fffffff + 1000
+	sender := reporter + 1
+	messageID := int(now.UnixNano()&0x3fffffff) + 1
+	message := domain.EphemeralMessage{
+		ID: messageID, Peer: domain.Peer{Type: domain.PeerTypeChannel, ID: reporter + 2},
+		SenderUserID: sender, ReceiverUserID: reporter, Date: int(now.Unix()), RandomID: 99,
+		Content:      domain.EphemeralContent{Message: "abuse evidence"},
+		OriginDevice: domain.EphemeralDevice{UserID: reporter, BusinessAuthKeyID: [8]byte{1, 2, 3}, SessionID: 44},
+		Version:      1, CreatedAt: now, ExpiresAt: now.Add(domain.EphemeralMessageRetention),
+	}
+	report := domain.NewEphemeralAbuseReport(reporter, "spam", "review this", message, now)
+	store := NewEphemeralReportStore(pool)
+	created, err := store.CreateEphemeralReport(ctx, report)
+	if err != nil || !created {
+		t.Fatalf("create=%v err=%v", created, err)
+	}
+	t.Cleanup(func() {
+		_, _ = pool.Exec(ctx, "DELETE FROM ephemeral_abuse_reports WHERE reporter_user_id = $1", reporter)
+	})
+	if created, err := store.CreateEphemeralReport(ctx, report); err != nil || created {
+		t.Fatalf("retry create=%v err=%v", created, err)
+	}
+	var evidenceRaw []byte
+	var count int
+	if err := pool.QueryRow(ctx, `
+SELECT evidence, count(*) OVER ()
+FROM ephemeral_abuse_reports
+WHERE reporter_user_id = $1 AND channel_id = $2 AND ephemeral_message_id = $3
+`, reporter, message.Peer.ID, message.ID).Scan(&evidenceRaw, &count); err != nil {
+		t.Fatal(err)
+	}
+	if count != 1 {
+		t.Fatalf("rows=%d", count)
+	}
+	var evidence map[string]any
+	if err := json.Unmarshal(evidenceRaw, &evidence); err != nil {
+		t.Fatal(err)
+	}
+	if evidence["MessageID"] != float64(message.ID) || evidence["Content"] == nil {
+		t.Fatalf("evidence=%s", evidenceRaw)
+	}
+	if _, leaked := evidence["OriginDevice"]; leaked {
+		t.Fatalf("device identity leaked into report evidence: %s", evidenceRaw)
+	}
+}