feat(roblox): support Rojo project mappings

[cayasde]

Summary

• Add optional roblox.rojo_project support backed by Rojo sourcemaps.
• Mount Rojo-mapped project modules and dependencies into game, including sources outside discovery roots.
• Preserve symbolic-link mappings and prevent project packages from replacing the configured Lutest test library.

Why

Roblox suites can use the same imports as the game, including Rojo-managed dependencies.

Validation

• lutest test
• mise run check
• Windows release-binary smoke tests and a remote Roblox run against a Rojo project (68 tests passed)

Close #67