Filter out Next.js internal and unknown server boundaries
Added filtering logic to exclude:
- Boundaries where the server component is "<unknown>"
- Boundaries where either file path contains Next.js internal paths
(packages/next/dist/, /next/dist/, node_modules/next/)
This reduces noise and focuses on user-defined boundaries.
Before filtering: 22 boundaries detected (including framework internals)
After filtering: 2 user boundaries detected
Part of boundary detection feature for identifying server→client
component boundaries in App Router applications.
