fix: skip unreadable files during indexing instead of crashing
On macOS with iCloud Drive (especially shared folders), some files may
appear in the filesystem but return EAGAIN (error -11) when read via
Node's readFileSync. This happens when iCloud has evicted the file
content but the file metadata remains visible.
Previously this crashed the entire update process. Now we catch the
error and skip the file, allowing the remaining files to index
successfully.
Affects: iCloud Drive shared folders on macOS
Error: 'Unknown system error -11: Unknown system error -11, read'
Reproduces with: Node.js v25.x, readFileSync on evicted iCloud files