## Why
Filesystem lookups by thread or rollout ID check whether unrelated compressed rollouts have an uncompressed sibling. These checks are unnecessary when the filename does not match the requested ID.
## What changed
Apply the thread or rollout ID filter before resolving plain/compressed file precedence. Preserve preference for uncompressed files and selection of the newest rollout for a thread.
## Testing
Extend lookup tests to cover unrelated compressed files, uncompressed-file precedence, missing rollout IDs, and rollout ID tie-breaking for files with the same timestamp.
GitOrigin-RevId: 5bdb56ebec8031fceb5f6adbfcf644ad010e52f2