Fix memory errors and segmentation faults in test suite

[krystophny]

Problem

Multiple tests are failing with segmentation faults and memory errors after updating to the latest fortfront.

Affected Tests

• test_fortfront_api_capabilities.f90 - Segmentation fault in type deallocation
• test_fortfront_integration_readiness.f90 - Array bounds error in type system
• Several other tests with similar memory issues

Error Examples

1. Segmentation fault in type system:

Segmentation fault - invalid memory reference
at build/dependencies/fortfront/src/semantic/type_system_hm.f90:956
in __type_system_hm_MOD___deallocate_type_system_hm_Mono_type_t

2. Array bounds error:

Index '1' of dimension 1 of array 'rhs%args' above upper bound of 0
at build/dependencies/fortfront/src/semantic/type_system_hm.f90:410

Root Cause

Likely related to changes in fortfront's type system and memory management after PR #101.

Solution

• Review and fix memory management in fluff's integration with fortfront
• Update test cases to properly handle new fortfront API
• Add bounds checking where necessary