crypto: add signDigest/verifyDigest and Ed25519ctx support

[panva]

notable-change PRs with changes that should be highlighted in changelogs. 👇

Adds crypto.signDigest() and crypto.verifyDigest(), one-shot functions that sign/verify a pre-computed hash digest directly, without hashing internally.

---

const digest = crypto.createHash('sha256').update(data).digest();

const sig = crypto.signDigest('sha256', digest, privateKey);
const ok = crypto.verifyDigest('sha256', digest, publicKey, sig);

Supports RSA (PKCS#1 v1.5, PSS), ECDSA, DSA, Ed25519, and Ed448.

Also adds Ed25519 context string support to crypto.sign(), crypto.verify() as well as the new methods.

Resolves: #60263

Pre-hash variants of Ed25519 and Ed448 as well Ed25519 context is defined in RFC8032

[nodejs-github-bot]

Review requested:

• @nodejs/crypto
• @nodejs/security-wg

[github-actions]

The notable-change PRs with changes that should be highlighted in changelogs. label has been added by @panva.

Please suggest a text for the release notes if you'd like to include a more detailed summary, then proceed to update the PR description with the text or a link to the notable change suggested text comment. Otherwise, the commit will be placed in the Other Notable Changes section.

[codecov]

Codecov Report

❌ Patch coverage is 81.66667% with 22 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.69%. Comparing base (b328bf7) to head (ce13128).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/crypto/crypto_sig.cc	76.13%	9 Missing and 12 partials ⚠️
lib/internal/crypto/sig.js	96.42%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##             main   #62345    +/-   ##
========================================
  Coverage   89.68%   89.69%            
========================================
  Files         676      676            
  Lines      206689   206798   +109     
  Branches    39579    39615    +36     
========================================
+ Hits       185370   185484   +114     
+ Misses      13450    13444     -6     
- Partials     7869     7870     +1     

Files with missing lines	Coverage Δ
lib/crypto.js	93.04% <100.00%> (+0.07%)	⬆️
src/crypto/crypto_sig.h	63.63% <ø> (ø)
lib/internal/crypto/sig.js	95.98% <96.42%> (+0.25%)	⬆️
src/crypto/crypto_sig.cc	71.52% <76.13%> (+1.18%)	⬆️

... and 26 files with indirect coverage changes

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[ChALkeR]

Not entirely certain how this works, will test