…lt export (backlog #2)

The app now consumes dekereke_core (path dependency). Importing a
.dektask replaces the wordlist with the task's subset — entries keep
their DkSyncIDs (task.json ID map, D2) — stores the task config, and
unpacks bundled reference audio (task_audio/) and pictures. Plain-XML
import returns the app to normal mode.

Elicitation becomes task-driven when a task is active: visible prompt
fields (first one large), playable reference columns resolved by the
suffix rule (bundled as WAV or FLAC — D3's one exception), and writable
columns collecting text and/or 16-bit mono WAV recordings named
<SoundFile base><suffix>.wav. One value per cell is stored in new
task_values/task_recordings tables (DB v3, additive migration).

Export produces a .dekresult (values + recordings + consent log),
checked with the core validateResult before writing so a bad archive
can never reach the researcher.

Records with empty/duplicate References are skipped at task import with
a plain-language message (this app keys entries by Reference); audio
columns without a suffix are rejected outright.

All 45 pre-existing tests stay green; 24 new task tests.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LebVeDXrBBU46RpZ2kQET5

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LebVeDXrBBU46RpZ2kQET5