Release v4.103.0

Added

• MCP propose-move moves a slice to another feature, or a feature to another module or feature, as a reviewable proposal that keeps every semantic and event-contract identity, repairs references (including screen actions and depends on), and refuses moves that would change inherited authorization or interaction behaviour, collide with an existing name, or lose an identity (#386)
• screenplay contract writes a versioned, machine-readable contract of the language: keywords and constructs, every diagnostic with its severity and title, every MCP tool and CLI command with their parameters, and which constructs each executable model version admits. Every fact is derived from the compiler, and the contract ships as a release asset and inside the Cratis.Screenplay.Tool package (#500)