Add SHA256 fallback validation for ESDs and update catalogs with SHA256 fields

[KatsuhiroWatanabe]

Summary

This PR adds SHA256 support for validating downloaded ESD files in OSD.
When a catalog entry does not provide a SHA1 hash, the script now falls back to SHA256 verification to prevent corrupted images from being used.

Details of Changes

• Public/OSDCloud.ps1

  • Add SHA256 fallback logic when the catalog does not include a SHA1 value.
  • Compare the downloaded ESD’s SHA256 with the catalog value.
  • Halt execution on mismatch to ensure image integrity.

• Catalog updates (add Sha256 fields)

  • cache/archive-cloudoperatingsystems/CloudOperatingSystems.json
  • cache/archive-cloudoperatingsystems/CloudOperatingSystems.xml
  • cache/archive-cloudoperatingsystems/CloudOperatingSystemsARM64.json
  • cache/archive-cloudoperatingsystems/CloudOperatingSystemsARM64.xml
  • Source of truth: SHA256 values are based on the Windows 11 build 26200.7462 ESD information from cache/os-catalogs/build-operatingusystem.xml.

Motivation

Starting with Windows 11 25H2, Microsoft provides SHA256 (not SHA1) for ESD integrity.
Classic OSD, however, only validated SHA1 and its catalogs did not expose a Sha256 field.

As discussed in OSDeploy/OSD#317, I needed a working implementation on my side.
This PR adds a SHA256 fallback in OSDCloud.ps1 and introduces Sha256 fields to the catalogs so ESDs can be verified reliably when SHA1 is unavailable.

The SHA256 values were populated from cache/os-catalogs/build-operatingusystem.xml for build 26200.7462.

Compatibility

This change is backward‑compatible:

• SHA1 validation remains unchanged.
• SHA256 is used only when the catalog does not provide SHA1.
• Existing catalogs without a Sha256 field continue to work normally.