Expand portable CLI compatibility and release 0.6.3

[Marc-André Moreau (mamoreau-devolutions)]

Summary

• add portable Azure Artifact Signing for PowerShell Authenticode scripts and module payloads
• expose portable signature removal, detached/catalog verification, RFC3161 PE timestamping, PFX/local signing, and expanded Azure Key Vault format/batch support
• preserve UTF-16 PowerShell signatures, safe terminal signature removal, and repeated --append-signature target behavior
• bump Rust workspace crates, PowerShell module, and NuGet tool to 0.6.3

Validation

• cargo clippy -p psign --all-targets --locked -- -D warnings
• cargo check -p psign --no-default-features --locked
• focused portable removal, certificate-store/PFX, detached/catalog verify, timestamp, Azure Key Vault batch, and Artifact Signing PowerShell tests

cargo test --workspace --locked was attempted; portable CLI tests passed, while Windows corpus verification failed because the local WinVerifyTrust store does not trust the test certificates (0x800B0109).