Add unit tests for PropositionFactories factory functions

[rizumita]

Description

The PropositionFactories.swift file contains the global makeProposition factory function that creates ClosureTemporalProposition instances, but there are no corresponding tests for this functionality.

Tasks

• Create PropositionFactoriesTests.swift in the Core tests directory
• Test makeProposition with various state types and return types
• Test that the created propositions have correct IDs and names
• Test that the evaluation closure is properly wrapped
• Test edge cases with different Hashable types

Priority

Medium

Location

Sources/TemporalKit/Core/PropositionFactories.swift