Bootguard, CSME and Intel gen 14th+ (Meteor Lake): S3 deprecated but still functional. Might break with future firmware/microcode updates

Nobody has claimed this yet.

Current state https://github.com/linuxboot/heads/issues/1801#issuecomment-2532372097:
> ME is now disabled and S3 is enabled and functional: [#1846 (comment)](https://github.com/linuxboot/heads/pull/1846#issuecomment-2532346570)
>
> As I mentioned elsewhere, **it's not supported by Intel so if it breaks with some update to silicon or fw there's a good chance they won't fix it (that's what happened with Tiger Lake), but right now it seems to work well**

_So S3 works as of now, so no need to enable ME/CSME to have s01x sleep yet. Read still: might break, and next gen will mostly require ME/CSME._

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OLD
~ME/CSME is now required (cannot be disabled) to obtain S0ix sleep state. S3 is not possible on newer Intel platforms.~
~So user has to switch ME on to suspend (sleep), or accept that no sleep is possible. Note that hibernation is not possible on QubesOS (Xen). So this means important change on UX.~
~This is true on Intel gen 13+, ie NovaCustom V56 14th Gen, amongst others.~

This proved to be wrong statement, not so late after QubesOS mini-summit 2024, it was proven that Novacustom V56/Nitropad V56 Intel CPU gen 14th CAN do S3 still. So this problem is reported for next gen, CSME/ME not required for sleep YET:
> ME is now disabled and S3 is enabled and functional: [#1846 (comment)](https://github.com/linuxboot/heads/pull/1846#issuecomment-2532346570)
>
> As I mentioned elsewhere, it's not supported by Intel so if it breaks with some update to silicon or fw there's a good chance they won't fix it (that's what happened with Tiger Lake), but right now it seems to work well

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There seems to be a confusion from community around possibility of getting Clevo laptops with unfused bootguard keys and being able to flash custom firmware on those Clevo laptops. Clarify that Clevo laptops have unfused bootguard keys only if ordered through Novacustom bulk orders from Clevo to be rebranded and distributed with Dasharo firmware.

Review the current and struck-through statements in issue #1801, then follow the referenced #1846 pull request comments about ME/CSME and S3. Clarify the supported sleep-state status for Intel generations and the conditions for Clevo systems with unfused Bootguard keys; done means the community guidance is accurate and no longer contradictory.

Written by the indexing model from the issue text.