fix: only interrupt startup for real configuration problems

Found while walking the task 13 checklist against real mail. Item 1
("startup shows no configuration warnings with a valid config") failed:
with a perfectly valid config that simply had no [sync] command, every
launch opened a blocking modal that had to be dismissed before the window
could be used.

Config now separates the two cases. A problem is something configured but
wrong (a sync command that does not exist, an account with no maildir);
those still open a dialog, as does every KeyMap warning, since each one
means a binding the user wrote is being ignored. A notice is an optional
feature simply not being configured; it reports to the status bar only.
Nothing is broken in that case, and a modal on every launch teaches the
user to dismiss dialogs unread, which defeats the ones that matter.

problems() is a subset of warnings(), so callers wanting everything need
only the latter.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

0 files changed, 0 insertions, 0 deletions