feat(extension): support grouped updates

[43081j]

This makes the existing "group updates" setting work.

When enabled, repeated updates of the same tree will be grouped into one node with a count.

The updates are not lost, in that the setting can be disable to re-expand the nodes.

Fixes #736

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Screen.Recording.2025-08-28.at.11.22.02.mov

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[JoviDeCroock]

One remark from your video, should we do 2 -> 3 -> 4 or 2 -> 4 - currently it sais 2 - 3 but I wouldn't do that as it shows only the first value evolution rather than the full story

[43081j]

if we want to do that, i wonder if we should introduce a RenderedSignalUpdate type which would also solve my count issue (since the RenderedSignalUpdate would have a count, removing the need for the WeakMap and count props etc)

it could also then have a firstValue or some such thing

[43081j]

how about this @JoviDeCroock ?

we don't really need 2 tree types for this part imo

since this interface already represents a rendered update, it may as well have an optional count?

sorry i commented on the wrong thing. i meant to comment on the UpdateTreeNode

[43081j]

https://github.com/preactjs/signals/pull/752/files#diff-5069dab31e4d4d79bc03f108e66ff3bb5947b5b3c1a423099b024e178a817603R11

[43081j]

should we do 2 -> 3 -> 4 or 2 -> 4

i did get this working, but without showing the full path i think it gets confusing

this is actually telling us the first value was 0, a bunch of changes happened, then the value was 5, then 6.

the gap from 0 to 5 i think is more confusing than not having this

but if we do 0 -> 1 -> 2 -> 3 -> 4 -> 5 -> 6 - things will get pretty long, quickly

edit:

this kinda works a bit better