Replace 30+ hardcoded strings across 15 components with $t() calls.
Added keys for common actions, drawers titles, empty states, and modals.
Ticket: T-020
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Fix TaskStatus getter naming (isFinal -> getIsFinal) so Symfony serializer
properly exposes the isFinal field. Add archive/unarchive buttons and
non-final tasks info message to TaskGroupDrawer. Remove obsolete TaskType
entity and repository.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>