Spec #38.6: Implement implicit array allocation

[treytomes]

Description

ECMA-55 auto-allocates arrays on first reference without explicit DIM. Default bounds are BASE to 10.

ECMA-55 References

• ECMA55-ARR-010: Implicit array allocation
• ECMA55-ARR-011: Default bounds are 0-10 or 1-10 based on BASE

Acceptance Criteria

• First access to undeclared array allocates it
• Default bounds: BASE to 10
• Respects current OPTION BASE setting
• Works for both 1D and 2D arrays
• Subscripts must fit within default range
• Mix of explicit DIM and implicit allocation works
• All tests pass
• Test coverage ≥ 80%

Parent Issue

Part of #38 - Implement DIM and OPTION BASE for array support

Estimated Effort

2-3 hours

Dependencies

Depends on Spec #38.5 (2D array support)