WFFunctionCall exposes function_ and argumentMap_ directly to its consumers (notably WFImplementation.evaluate). The TODO at WFFunctionCall.js:80 calls for proper accessors so internal representation can change without rippling out.
Small ergonomic / encapsulation fix; good first-task material.
Desired behavior/Acceptance criteria
- Add getFunction() and getArgument(key) / getArguments() accessors to WFFunctionCall.
- Replace direct function_ / argumentMap_ reads at the call sites in src/transpilation/ with the new accessors.
- Trailing underscore convention for "private" stays — readers outside the class should use the accessors.
- All existing tests pass.