PM-32154: Feat: Update salt for new registration model

[david-livefront]

🎟️ Tracking

PM-32154

📔 Objective

This PR updates the RegisterFinishRequestJson to use the new salt structure.

[github-actions]

🤖 Bitwarden Claude Code Review

Overall Assessment: APPROVE

This PR reshapes RegisterFinishRequestJson to send MasterPasswordAuthentication / MasterPasswordUnlock blocks (kdf + salt + hash / wrapped user key) instead of the flat masterPasswordHash, userSymmetricKey, kdfType, and kdfIterations fields, and updates the AuthRepositoryImpl.register call site to pass kdf.toKdfRequestModel() and salt = email. The convenience secondary constructor mirrors the pattern already established by SetPasswordRequestJson and ResetPasswordRequestJson, including containedKeyId = null and reusing the same KdfJson for both blocks. Salt handling matches the existing feature-flagged v2 path in the same function (postKeysForUserPasswordRegistration(email = email, salt = email, ...)) and the hash it accompanies is derived by the SDK from the same email, so authentication and unlock data stay consistent. All four constructor call sites in the repo were updated and the affected unit tests were adjusted accordingly.

Code Review Details

No findings.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.12%. Comparing base (0945093) to head (77c440a).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7324      +/-   ##
==========================================
- Coverage   86.43%   86.12%   -0.31%     
==========================================
  Files         925      899      -26     
  Lines       66843    65888     -955     
  Branches    10009     9997      -12     
==========================================
- Hits        57778    56749    -1029     
- Misses       5523     5599      +76     
+ Partials     3542     3540       -2     

Flag	Coverage Δ
app-data	18.01% <100.00%> (+0.32%)	⬆️
app-ui-auth-tools	18.88% <0.00%> (+0.22%)	⬆️
app-ui-platform	16.29% <0.00%> (-0.31%)	⬇️
app-ui-vault	27.26% <0.00%> (-0.62%)	⬇️
authenticator	6.03% <0.00%> (-0.05%)	⬇️
lib-core-network-bridge	4.07% <0.00%> (-0.02%)	⬇️
lib-data-ui	1.20% <0.00%> (-0.01%)	⬇️

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