Function discoverRepos

discoverRepos(rootDir: string): RepoSource[]
Walk a directory tree, parse every recognized project manifest, and return the discovered GitHub repos with provenance.

The walk is recursive but never descends into the directory names listed in isExcludedDir (vendored deps + build artifacts). Duplicate repos are collapsed to a single RepoSource keyed by the first manifest seen, and the returned list is sorted by repo for deterministic output.

Filesystem errors at individual nodes (permission denied, unreadable file) are swallowed: a single broken file should not abort discovery across the rest of the tree.
Parameters
- rootDir: string
  the directory to scan; may be relative or absolute
Returns RepoSource[]
a sorted, deduped array of RepoSource records
Example
```
discoverRepos('.')
  // => [{ file: '/abs/path/package.json', repo: 'StoneCypher/issue_tree',
  //       manifest: 'package.json' }]
```
- Defined in cli/detect-repos.ts:817