File-Based Ownership

The initial "unit" was "modules" in #invert and Code References was bolted on later. Code References DO support owner which overrides that of the module it's in (Was required for @TestOwner).

I agree that based on where we are today, we should actually lean towards file-based ownership instead of module based as a default.

Proposed logic:

• If a CodeReference has an explicit owner attached to it, use it (Nice for custom situations that override file/module based ownership methods).
• After collection, if no owner is manually added, compute file-based ownership.
• If file-based ownership doesn't come back to anything, then fall back to module ownership.

Thoughts about a required owner field for CodeReference:

Right now owner :String? is nullable. We could change that to non-null, but it would require updating all collectors to have explicit awareness to add file-based ownership.
Based on this "breaking" change, and because it makes authoring Collectors more complex, I would lean towards keeping it nullable, and use the proposed logic above.

Start by tracing CodeReference and the collectors that populate ownership. Verify that explicit CodeReference owners take precedence, file-based ownership is computed when no owner is supplied, and module ownership is used only as a fallback while owner remains nullable.