4ec3eb7cee
Add SCAN_AHEAD_LIMIT (10000 lines) to get_line() in Sampling state. Without this, jumping to end-of-file (G) during progressive loading would scan the entire file byte-by-byte on the main thread, blocking the UI and consuming excessive memory. Lines beyond the scanned region + limit now return None, which the TUI renders as empty. Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent) Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>