Fix filter mode to handle all taskwarrior filter expressions correctly

Replace strings.Fields with shlex.Split in the filter input handler so
that quoted attribute filters like description:"my task" are passed as a
single argument rather than being split on whitespace. This makes proj:xxx,
+tag, and any other valid taskwarrior filter expression work correctly when
entered via the interactive f key in both traditional and ultra mode.

Also propagate taskwarrior errors from reload() back to the user via the
status bar instead of silently discarding them, so invalid filters produce
visible feedback. On error the filter is rolled back to nil to avoid
leaving the UI in a broken empty-list state.

Extracts the filter-string parsing into a testable parseFilterInput helper
in helpers.go and adds comprehensive tests in helpers_test.go.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

0 files changed, 0 insertions, 0 deletions