[Bug][move-compiler-v2] Double-check whether path canonicalization is needed for `move-model::add_source` and elsewhere

[brmataptos]

🐛 Bug

move-compiler-v2 and move-model use file names as keys for things. But they are also used as user-visible outputs. We need to double-check that we aren't double-compiling or missing properties due to files reachable on multiple paths somehow.

[brmataptos]

For example, see move-model/src/lib.rs near line 188:

target_sources_names.contains(fname.as_str()),