feat: support DW_TAG_enumeration_type and DW_TAG_enumerator

[abroooo]

This PR improves the debug information generation for enumerations by representing them as proper DWARF enumeration types instead of type aliases.

Improves debug information generation for enumerations by representing them as proper DWARF enumeration types instead of type aliases.

Changes:

• enhance enum debug info: enums are now emitted as DW_TAG_enumeration_type with proper enumerator entries for each variant, making them fully visible in debuggers with their symbolic names and values
• update inkwell to 0.8: use inkwell 0.8 release which provides create_enumeration_type and create_enumerator APIs
• refactor call expression handling: Updated expression generator to use inkwell's new CallSiteValue::try_as_basic_value().basic() API

Before vs After:

Before: enums appeared as simple integer typedefs in debug info
!DIDerivedType(tag: DW_TAG_typedef, name: "en1", baseType: !9)

After: enums are represented as enumeration types with their variants
!DICompositeType(tag: DW_TAG_enumeration_type, name: "en1", baseType: !13, elements: !5)
!5 = !{!6, !7, !8}
!6 = !DIEnumerator(name: "a", value: 0)
!7 = !DIEnumerator(name: "b", value: 1)
!8 = !DIEnumerator(name: "c", value: 2)

This allows debuggers to display enum values by their symbolic names rather than raw integer values.

[mhasel]

nice