They have none of it. Zilch. They have, essentially, a committee of people focused on elections that say a lot of nice vaguely leftist words and implement zero accountability. The people on those committees regularly get paid positions on these campaigns and it is no surprise that they are very defensive of the concept that an "elected" is failing. It is a collaborative relationship mediated by cash and proximity to electoral power.

Regarding the specifics:

NYCDSA leads the charge against electoral accountabikity. They push back against it, not for it, and have never unendorsed a candidate they ran.
The Mamdani campaign is not financially or organizationally dependent on the DSA. This is why he is shmoozing with ghouls. In classic DSA electoralist fashion, it is a one-way street in terms of direct benefit and control: Mamdani receives some resources but does not need them exclusively, nor is he in any way afraid of losing the free volunteers and fundraising. What are they gonna do, unendorse? Kick him out? lmao
Mamdani was not a regular member when he ran for state legislature. He didn't do jack shit and had no internal vetting outside of one of these committees saying, "yeah okay".

The extent of interviews and holding to lines is just one of those rubber stamp committees. It is not serious and it has no actual standards. They are like union endorsement decisions, it is just 4-5 liberals calling someone that loves cops a "real progressive" that is "fighting for the working class". Their filter just keeps out those who step too far outside of liberal hegemony or don't have a list of how many doors they need to knock (it doesn't meed to be a plausible list).

The question is whether the membership is really brave/united enough to pull the plug when they can practically taste the sweet victory of an election in less than 3 weeks.

NYCDSA membership, by and large, reflects the practices above. Pull the plug? They are more likely to approve the resolution saying not to criticize Mamdani now or once in office. Their electoral approach adopts the form and function or bourgeois electoral systems, they are protective of the climber system and investing in cheerleading and donating and volunteering regardless of what a candidate or "elected" says or does. It is an anti-participatory process that is more like an NGO than a political organization that believes in anything.

They actively avoid having policy positions on which to have discipline. These are the folks that opposed the anti-Zionist resolutions for years and years and are only now transforming once it is somewhat popular among liberals.

They should have some sort of mechanism to act that quickly or at least make a credible threat as I heard somewhere that mamdani has to attend weekly (general membership?) meetings

This requires a substantial change in membership, leadership, and associated political orientation. Any theoretical mechanusm doesn't matter if nobody enforces it or cares about it or worse, if they actively oppose it. This is why my answer focused on the need to do actual organizing and education into a proper political program and not just whatever is stated on a resolutions. NYCDSA, like any chapter, can always have a big membership vote on anything at least once per month, and can give these committees "emergency" powers to reject candidates, etc. But that means nothing if there is no will to use it. Kind of like how CA Dems never override their governor's veto.

I've only seen a couple examples of left organizations with good discipline in my life and none that were involved with electoralism.

SA has pretty good discipline and was successful at electoralism. Unfortunately they are Trots with a lot of shit takes and bad ideas, but theor level of organization and discipline puts DSA to shame.

Most communist orgs have pretty good discipline. Their members avoid criticizing their own org publicly, for example. Any time I criticize PSL here, I assume none will publicly agree, and some will defend against the criticism. Part of this is naturally defending one's own group and ideas they agree with and part of this is internalized discipline. I assume that some part of my criticism may register internally locally, but not publicly.

I don't know how that could be integrated into an elected position like mayor, really. He can't be micromanaged by hundreds or thousands of people.

Why would this be the only way? Committees and the fear of being recalled means no need for mass micromanagement. It begins with openly withdrawing support for "electeds" by having a policy line and sticking to it. Once that fails in its own way, they can commit to and build more structure, etc etc.