Release v7.4.0

Added

• SetAIProviderHarnesses sets the complete list of agent harnesses a provider may run jobs through, rejecting duplicates, unknown providers and harnesses the provider's vendor or credential cannot run. An empty list disables harness dispatch for that provider without affecting chat completions (Cratis/Direct#936)
• AIProvider and ConfiguredAIProvider expose SupportedHarnesses and HasHarnessSelection, so a consumer can tell a provider that was never configured apart from one that was deliberately disabled (Cratis/Direct#936)
• Copilot providers now appear in ConfiguredAIProvider, with their credential kept current as they connect and disconnect (Cratis/Direct#936)

Deprecated

• The per-agent Harness on ConfigureAgent is kept for existing callers and as a fallback for providers with no harness selection; configure harnesses on the provider instead (Cratis/Direct#936)