[monsterlag]

A selected .nup that is missing or unavailable currently reaches the Builder's unexpected-exception handler. Report the failing path and OS reason through the normal error message, with guidance to reconnect the drive or choose the file again. Existing extraction and cache reuse behavior stays unchanged.

Thanks to @biellbomfim for the report. Refs #1232.

Validation:

• All 8 authored cli() / main() regression cases pass on Windows and WSL after merging upstream 7dbdcdc into ccc6fb2.
• Untouched main previously failed the five missing/access-error cases while all three controls passed with the identical fixture. Controls preserve extraction requests, matching-cache reuse and unexpected programming-error reporting.
• Existing game-free NUP cache tests and the strict selected runner previously passed on both platforms. All eight hosted validation checks passed on prior head 5375552; all nine hosted validation checks pass on the refreshed head, including the DLSS link check; release publishing is skipped for the PR.
• The final PR diff contains only the diagnostic and its regression fixture. The 512 MiB output-pool expectation is already in upstream main and is retained unchanged.

Only temporary authored files and stat-error doubles were used. No GUI, SDK/compiler, game, or real permission-denial scenario was exercised. This improves the missing/unavailable-input diagnostic; it does not establish why the reporter's path was unavailable or restore missing files.

[hckrman101]

Looks good. The os.stat on the selected .nup is now wrapped and goes through fail(), so a missing or unavailable package gives the normal @@error with the path and the OS reason instead of the unexpected-exception handler. It's only the stat that's caught, so extraction and cache reuse are untouched, and genuine programming errors still reach the traceback path (the RuntimeError test covers that). tests/test_missing_nup.py is picked up automatically by run_all.py's tests/test_*.py discovery, it launches nothing and only touches temp dirs, and CI is all green including both Python source check jobs.