feat: Implement DefaultCryptoHmac for compliance-aware HMAC operations

- Added DefaultCryptoHmac class implementing ICryptoHmac interface.
- Introduced purpose-based HMAC computation methods.
- Implemented verification methods for HMACs with constant-time comparison.
- Created HmacAlgorithms and HmacPurpose classes for well-known identifiers.
- Added compliance profile support for HMAC algorithms.
- Included asynchronous methods for HMAC computation from streams.

.gitea/workflows/lnm-vex-backfill.yml

@@ -25,7 +25,7 @@ jobs:
   vex-backfill:
     runs-on: ubuntu-22.04
     env:
-      DOTNET_VERSION: '10.0.100-rc.1.25451.107'
+      DOTNET_VERSION: '10.0.100'
       ARTIFACT_DIR: ${{ github.workspace }}/.artifacts
     steps:
       - name: Checkout