Spark DSL transformer that generates CanPerform calculations from DSL entities.

This transformer reads can_perform entities and the can_perform_actions option from the ash_grant section and adds corresponding boolean calculations using Ash.Resource.Builder.add_new_calculation/5.

Usage Rules

• can_perform_actions (batch) and can_perform (individual entity) can coexist. Both are merged into a single list before generating calculations.
• Naming: can_perform_actions [:update] generates :can_update?. can_perform :update also generates :can_update? by default. Use the name: option on can_perform for a custom name (e.g., name: :editable?).
• Duplicate handling: Uses add_new_calculation (not add_calculation), so if the same calculation name already exists (from an explicit calculations block or a duplicate DSL entry), it is silently skipped. The first definition wins.
• Coexistence with explicit module: DSL-generated calculations and manually declared {AshGrant.Calculation.CanPerform, ...} calculations coexist safely.
• Resource auto-detection: The transformer injects the resource module automatically via Transformer.get_persisted(dsl_state, :module), so users do not need to pass resource: __MODULE__ when using the DSL.
• Public by default: All DSL-generated calculations are public?: true by default. The can_perform entity supports public?: false for private calculations.
• Action validation: At compile time, the transformer verifies that each referenced action name exists on the resource. A typo like can_perform_actions [:foobar] raises a Spark.Error.DslError with the list of available actions.