liboqs 0.16.0 release candidate 1

[xuganyu96]

This pull request resolves #2405.

Summary

Version numbers were updated in top-level CMake list files. Release notes and security notes were correspondingly updated, as well.

I ran the markdown linter from #2446 on RELEASE.md, hence the overhaul in formatting. I am also experimenting with release notes format. This release note is different from the previous ones in that the significant change section has sub-sections that provide further explanation instead of the one-liners in other sections.

As of June 19, #2446 is the only outstanding item. Considering that it is an infra/devtools pull request, I think it's okay to drop it for 0.16.0-rc1 if it is not ready for merging in a few days. We can include it for 0.16.0 full release or 0.17.

For reviewers, please help with proofreading the release notes. Thank you.

[coveralls]

coverage: 82.293% (-0.007%) from 82.3% — release/0.16.0-rc1 into main

[xuganyu96]

0.16.0-rc1 release road blocks

In order or decreasing priority:

• Resolve Intel SDE download failure (Download Intel SDE from alternative source #2461, Switch linux_x86_emulated to download Intel SDE from alternative source #2463)
• Add updated information regarding algorithm support (Add updated information regarding algorithm support #2441)
• Fix uninitialized encaps_derand pointer dereference for NTRU KEMs (Fix uninitialized encaps_derand pointer dereference for NTRU KEMs #2460)
• Memory sanitizer test failures on Classic McEliece (Investigate weekly build failures #2436)
• Initial HQC integration (Update HQC implementation to 2025-08-22 version #2407 , Update HQC implementation to 2025/02/19 version #2118)
• Mention FrodoKEM algorithm change in release notes (Mention FrodoKEM algorithm change in 0.16.0 release notes #2405)
• OQS_MEM_BLACKBOX and its application to FrodoKEM (Implement value barrier and apply to FrodoKEM #2431)
• Update mlkem-native to v1.2.0 (Update mlkem-native to v1.2.0 #2470)
• Markdown linter (Add Markdown documentation linting #2446, Add documentation Markdown linter to CI #1785) (removed from 0.16.0 and moved to 0.17)

[baentsch]

0.16.0-rc1 is blocked by #2328

Shouldn't that read blocked by (review of) #2407?

[bhess]

LGTM, thanks @xuganyu96 !