Includes the required regression case: rewrite a file with different
content, force the original mtime back via os.utime, and assert the
fingerprint still differs (because size changed).
MainWindow._loaded_mtime -> _loaded_stat (core.ConfigStat), populated
via core.config_fingerprint() at load/save time. The save-path stale
check now compares the full fingerprint (mtime AND size) instead of
bare mtime equality.
Two prior attempts to fix this line via a literal or -escaped
non-breaking space both silently reverted back to a no-op regular-space
replace during transcription. Using chr(0xA0) instead removes any
non-ASCII or backslash-escape character from the source line entirely.
The previous commit accidentally normalized the non-breaking space
(U+00A0) in _normalize_unicode's replace() call to a regular space
during a copy/paste, turning that replace() into a no-op. Use an
explicit escape instead of the literal character so it can't
be silently corrupted again.
Bare mtime equality can miss a concurrent external write that lands
within the filesystem's mtime resolution (same-second writes), or
where the writer restores the original mtime. Add config_fingerprint()
returning a (mtime, size) ConfigStat pair; the stale-file check in
bcc.py now compares both fields instead of mtime alone. config_mtime()
is kept as-is (still used/tested independently).
The crashed/exited/stderr spawn tests used 0.3-0.5s timeouts. On a slow CI
runner, interpreter startup can exceed that, so the process is still starting
when the timeout fires, gets killed, and is misclassified "ok" (still running)
instead of "crashed"/"exited". Bump those three to 2.0s. The two "ok" paths
(sleep-60, stdin-block) stay at 0.3s since timing out there means success.