- Fix nested Lcx_GenerateStructInstance overwriting parent slot by
incrementing structCount BEFORE field processing
- Fix Lcx_LowerModule to skip generic structs from hm.structs (was missing
continue due to bootstrap compiler codegen limitation)
- Fix C backend to forward-declare ALL structs at top, removing second
generic-only forward declaration section that came too late
- Add empty-name guard in CBE_EmitStructDef
- Import system: parser supports ::* glob imports, sema two-pass resolution