Function computeTreeStatistics

computeTreeStatistics(files: readonly ScannedMarkdownFile[]): TreeStatistics
Aggregates per-file measurements into tree statistics.

A file counts as orphaned when no other scanned file holds a link resolving to it (inboundLinkCount === 0), so single-file scans report one orphan.
Parameters
- files: readonly ScannedMarkdownFile[]
  Scanned file measurements for the full scan
Returns TreeStatistics
Aggregate statistics with a stable field order
Example
```
const files = await scanMarkdownTree("./docs");
const statistics = computeTreeStatistics(files);

console.log(statistics);
```
- Defined in commands/tree.ts:102