}
        } catch (final Exception e) {
            logger.debug("Failed to remove heartbeat.", e);
        }
    }

    /**
     * Returns a list of currently active instances based on non-expired heartbeat documents.
     *
     * @return the list of active instances.
     */
    public List<InstanceInfo> getActiveInstances() {
        final List<InstanceInfo> instances = new ArrayList<>();

        assertEquals("Q2", request.getMessages().get(0).getContent());
        assertEquals("A2", request.getMessages().get(1).getContent());
    }

    // ========== addHistoryWithBudget — turn-based packing tests ==========

    @Test
    public void test_addHistoryWithBudget_turnBasedPacking_twoCompleteTurns() {
        final List<LlmMessage> history = new ArrayList<>();

OgW,UACPiC,EAAWjC,QAAUhW,EAAOgW,SAEhCiC,EAAWxY,GAAKO,EAAOP,GAAGxD,GAC1BiY,GAA0B+D,GAEtBna,EAAQma,KACRI,GAAmB,GAIvBD,GAAgBzb,EAAgBsb,GAAY/a,cAG5Ckb,GAAkE,GAAlDzb,EAAgBsb,GAAYlb,aAAaxB,OAEzDoB,EAAgBsb,GAAYM,MAAQH,EAE/BE,EAaGF,EAAeD,IACfA,EAAcC,EACdF,EAAaD,IAbE,MAAfE,GACAC,EAAeD,GACfE,KAEAF,EAAcC,EACdF,EAAaD,EACTI,IACAC,GAAoB,IAWpCnc,EAAO6D,EAAQkY,GAAcD,GAkDzBO,CAAyBxY,GAClB1D,EACP4X,GAA0BlU,GAc1BvE,EADAhB,GADiBuF,EAVDA,GAWDR,IAEfQ,EAAO5B,GAAK,IAAIxC,KAAKvB,EAAM0b,OACpBpa,EAAOlB,GACduF,EAAO5B,GAAK,...

E,EACfhC,KAAKC,SAAWH,6BAKlBiK,KAAA,WACEzL,EAAAA,QAAC,+CAA6E+F,IAAI,UAAW,SAC7FrE,KAAK6P,qBAGP5L,OAAA,SAAOsX,EAAcC,GAAU,IAAA7a,EAAAX,KACvByb,EAAgBnd,EAAAA,QAAEoD,MAxCR,yBA0ChB,GAAI1B,KAAKiG,QAAQkV,UAAW,CAC1B,IAAMO,EAAaF,EAASxS,SAASkS,IAAe9a,QAC9Cub,EAAeD,EAAW3a,KAAKka,IAAwB7a,QAC7DJ,KAAK2D,SAASgY,EAAcD,GAG9BF,EAAS5X,SAASkQ,IAClByH,EAAalR,OAAOnG,UAAUlE,KAAKiG,QAAQ/C,gBAAgB,WACzDsY,EAAS5X,SAASiQ,IAClBvV,EAAAA,QAAEqC,EAAKV,UAAUnB,QAAQ2c,MAGvBzb,KAAKiG,QAAQmV,eACfpb,KAAK4b,oBAITjY,SAAA,SAAS4X,EAAcC,GA...

,GA/TuB,IA+TnBA,EAAM0J,QAAiD,UAAf1J,EAAMsB,MAlUtC,QAkU0DtB,EAAMnI,IAC1E,OAGF,MAAMic,EAAczM,EAAetH,KAAKuR,IAExC,IAAK,MAAM7H,KAAUqK,EAAa,CAChC,MAAMC,EAAU3B,GAASpL,YAAYyC,GACrC,IAAKsK,IAAyC,IAA9BA,EAAQxN,QAAQuL,UAC9B,SAGF,MAAMkC,EAAehU,EAAMgU,eACrBC,EAAeD,EAAa/R,SAAS8R,EAAQxB,OACnD,GACEyB,EAAa/R,SAAS8R,EAAQzN,WACC,WAA9ByN,EAAQxN,QAAQuL,YAA2BmC,GACb,YAA9BF,EAAQxN,QAAQuL,WAA2BmC,EAE5C,SAIF,GAAIF,EAAQxB,MAAM5X,SAASqF,EAAMlC,UAA4B,UAAfkC,EAAMsB,MAzV1C,QAyV8DtB,EAAMnI,KAAoB,qCAAqCoO,KAAKjG,EAAMlC,OAAOiL...