Surface classification reasons more explicitly in repo details

[RichardGeorgeDavis]

Summary

Make repo classification reasons easier to inspect in Workspace Hub.

Problem statement

Classification is intentionally conservative, but contributors and operators still have to infer too much about why a repo was classified as Vite, static, WordPress, PHP, or unknown.

Affected area

• Workspace Hub repo details
• Repo classification display
• Related docs if needed

Expected outcome

The details view should make the classification basis more explicit, such as:

• the file or signal used
• the inferred repo type
• why the app chose that classification instead of another

Constraints or non-goals

• No rewrite of the discovery engine
• No plugin or extension system work
• Keep the current conservative classification model

Verification

• Open Workspace Hub in a mixed workspace
• Inspect a few different repo types
• Confirm a contributor can explain why each repo was classified the way it was