Never undo settings applied on the page: sync from NA Ingest, rebase stale drafts, guard the installer

- config.json is NA Ingest's live settings: the READY hours (Tue 14-22, Wed 9-19, Sun 5-14) and the
  auto-fix hours (Tue 14-22, Wed 9-21, Sun 6:30-14) set on the settings page.
- Settings page: a draft carries what its page started from. A tab that loaded the settings before
  they changed (an Apply elsewhere, a program update) now has only its own edits put on top of the
  live settings; before, it saved its whole older copy and Apply quietly undid the newer values
  (it took ready.prop_host out twice today).
- install.sh refuses (exit 4) to replace live settings that came from an Apply (their fingerprint is
  a history entry's sha_after) unless --replace-config; --keep-config still updates code only.
- Tests pin their own auto-fix and READY hours, so the campus can change its own; the exit-timeout
  test expects 310 s (the Tascam outlet power-cycle).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_readiness.py

@@ -19,6 +19,8 @@ sp.log.addHandler(logging.NullHandler())
 sp.log.propagate = False
 
 CONFIG = sp.load_config(os.path.join(ROOT, "config.json"))
+# The tests pin their own READY hours (the campus sets its own on the settings page).
+CONFIG["ready"]["due"] = [{"days": ["sat"], "start": "12:00", "end": "23:59"}, {"days": ["sun"], "start": "00:00", "end": "13:30"}]
 RC = CONFIG["ready"]
 WEDNESDAY = datetime(2026, 10, 14, 15, 0).timestamp()       # the week before the plan: gaps are amber
 SATURDAY = datetime(2026, 10, 17, 16, 0).timestamp()        # inside "due": gaps are red