The `extractRegion()` function in `sync-snippets.ts` used `indexOf()` to
find region markers like `//#region persistData`. This caused incorrect
matching when one region name was a prefix of another—searching for
`persistData` would match `//#region persistDataServer` first if it
appeared earlier in the file.
The fix detects the file's line ending style and appends it to region
markers, ensuring exact matches:
- `//#region persistData\n` no longer matches `//#region persistDataServer\n`
This corrects `docs/patterns.md` where the `persistData` code fence was
incorrectly showing server-side code instead of client-side localStorage
helpers.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>