Re-register the backbone pre-hook on every apply

[jjdejong]

Stacked on #1 — base is fix/video-latent-capture, so the diff here is the lifecycle change alone.

Problem

The backbone pre-hook registration is gated on a sentinel attribute:

if not getattr(backbone, HOOK_ATTR_BACKBONE, False):
    backbone.register_forward_pre_hook(backbone_pre_hook, with_kwargs=True)
    setattr(backbone, HOOK_ATTR_BACKBONE, True)

That sentinel lives on the backbone module, which model.clone() shares by reference. So from the second apply onward in a single ComfyUI process the gate is already set: the new pre-hook is never attached, and the first apply's closure stays live — writing captured_latent_shape and current_sigma into a state dict that nothing else can read.

Consequences for every apply after the first, for the lifetime of the process:

• latent_frame_0 silently returns unmodified output. captured_latent_shape stays None, so the hook bails at every block.
• skip_when_sigma_above stops working in all modes, including guide — current_sigma comes from the same dead closure.

Only the first prompt after a restart ever worked, which makes this easy to mistake for a functioning node: you see it work once, then never notice it stop.

The attn1 hooks in this same node already remove-and-re-register correctly, and LTXLatentAnchorAware does so for both its hook types — this path was the outlier.

Fix

Track the handle, remove any prior registration, re-register unconditionally. The bypass path now detaches the pre-hook too, rather than only dropping the sentinel — which previously left the hook attached and firing.

Verification

Applying three times against a shared module:

apply 1: state='run1' live_hooks=1
apply 2: state='run2' live_hooks=1
apply 3: state='run3' live_hooks=1

Each apply's own state dict is the one populated, and hooks don't accumulate.

Confirmed on a live LTX-AV run: before the fix a second apply logged video latent shape was never captured; after it, the same second apply reports HOOK ACTIVE.

[jjdejong]

Superseded by TenStrip#15, which carries both commits upstream. Branch retained.