Add MATLAB package namespace support (+PackageName/ folders)

[bardo84]

Category

Language and runtime compatibility for real codebases

Problem

RunMat does not yet support MATLAB package namespaces using +PackageName/ folders.

Intent

This is important for real MATLAB codebases and toolbox compatibility. Without it, many structured projects remain non-runnable even if their internal code would otherwise work.

Done When

• MATLAB package namespace resolution works for supported +PackageName/ layouts
• imports / lookups behave correctly for common package usage patterns
• representative coverage exists for package-based code organization