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/domain/ephemeral_test.go

@@ -0,0 +1,64 @@
+package domain
+
+import (
+	"errors"
+	"testing"
+	"time"
+)
+
+func TestValidateEphemeralContentBoundsAllRetainedVectors(t *testing.T) {
+	valid := EphemeralContent{
+		Message:  "hi 👋",
+		Entities: []MessageEntity{{Type: MessageEntityBold, Offset: 0, Length: 2}},
+		ReplyMarkup: &MessageReplyMarkup{Type: MessageReplyMarkupInline, Inline: [][]MarkupButton{{{
+			Type: MarkupButtonCallback, Text: "OK", Data: []byte("ok"),
+		}}}},
+	}
+	if err := ValidateEphemeralContent(valid); err != nil {
+		t.Fatalf("valid content: %v", err)
+	}
+
+	badBounds := valid
+	badBounds.Entities = []MessageEntity{{Type: MessageEntityBold, Offset: 5, Length: 2}}
+	if err := ValidateEphemeralContent(badBounds); !errors.Is(err, ErrEphemeralInvalid) {
+		t.Fatalf("entity bounds err=%v", err)
+	}
+	badKeyboard := valid
+	badKeyboard.ReplyMarkup = &MessageReplyMarkup{Type: MessageReplyMarkupKeyboard, Keyboard: [][]MarkupButton{{{
+		Type: MarkupButtonText, Text: "public keyboard",
+	}}}}
+	if err := ValidateEphemeralContent(badKeyboard); !errors.Is(err, ErrEphemeralInvalid) {
+		t.Fatalf("reply keyboard err=%v", err)
+	}
+	badRich := EphemeralContent{RichMessage: &MessageRichMessage{Blocks: make([]byte, MaxEphemeralRichBlocksBytes+1)}}
+	if err := ValidateEphemeralContent(badRich); !errors.Is(err, ErrEphemeralInvalid) {
+		t.Fatalf("rich bound err=%v", err)
+	}
+	badMedia := EphemeralContent{Media: &MessageMedia{Kind: MessageMediaKindPhoto}}
+	if err := ValidateEphemeralContent(badMedia); !errors.Is(err, ErrEphemeralInvalid) {
+		t.Fatalf("media shape err=%v", err)
+	}
+}
+
+func TestEphemeralStoredStateRejectsPartialDeviceAndInvalidTombstone(t *testing.T) {
+	now := time.Unix(1_800_000_000, 0)
+	message := EphemeralMessage{
+		ID: 17, Peer: Peer{Type: PeerTypeChannel, ID: 1001},
+		SenderUserID: 2001, ReceiverUserID: 3001, Date: int(now.Unix()), RandomID: 9,
+		Content: EphemeralContent{Message: "private"}, OriginDevice: EphemeralDevice{UserID: 3001},
+		PayloadHash: [32]byte{1}, Version: 1, CreatedAt: now, ExpiresAt: now.Add(EphemeralMessageRetention),
+	}
+	if err := message.ValidateStored(); !errors.Is(err, ErrEphemeralInvalid) {
+		t.Fatalf("partial device err=%v", err)
+	}
+	message.OriginDevice = EphemeralDevice{}
+	message.Deleted = true
+	message.Content = EphemeralContent{}
+	if err := message.ValidateStored(); !errors.Is(err, ErrEphemeralInvalid) {
+		t.Fatalf("version-one tombstone err=%v", err)
+	}
+	message.Version = 2
+	if err := message.ValidateStored(); err != nil {
+		t.Fatalf("valid tombstone err=%v", err)
+	}
+}