fix(mtproto): drop the remark fragment from tg proxy deep links

genMtprotoLink appended the panel remark as a URL fragment (tg://proxy?...&secret=...#remark). Because secret/server is the last query value, lenient Telegram parsers fold the "#remark" into it and the imported proxy breaks with "incorrect client random". Telegram proxy deep links have no name field, so emit a clean link on both the backend (internal/sub) and frontend (inbound-link.ts). The remark still shows as a separate tag in the inbound info modal, which reads it from genAllLinks, not the URL.

Guards: Go TestGenMtprotoLinkFields asserts no fragment; the frontend mtproto link test asserts no '#'.

internal/sub/service_mtproto_test.go

@@ -40,6 +40,9 @@ func TestGenMtprotoLinkFields(t *testing.T) {
 	if q.Get("secret") != mtprotoTestSecret {
 		t.Fatalf("secret = %q, want the client's FakeTLS secret", q.Get("secret"))
 	}
+	if u.Fragment != "" {
+		t.Fatalf("link carries a #%s fragment; tg://proxy links must have no remark fragment", u.Fragment)
+	}
 }
 
 func TestGenMtprotoLinkWrongProtocol(t *testing.T) {