feat: expand language dropdown to 23 EU languages

test: verify apkg export works end-to-end

fix: update Anki export file type from .zip to .apkg

refactor: rename export handler to csv_for_anki, update file_types to .zip

fix: export visible

feat: add APKG export button and event handlers to UI

fix: reseting to correct state when changing language

feat: restore Generate Cards button on parameter change after Phase 2

fix: cefr_dropdown adjusted to prevent crashing

fix: exporting files

fix: single-click export download and remove export status label

fix: export csv works

feat: wire CSV/APKG export into UI with gr.File download

feat: A0 removed and default to A2

fix: functionality intact after refactor

refactor: add build_ui() layout function and UI state helpers to widgets.py

fix: audio and images toggles when clicked on and off

feat: wire voice dropdown into TTS audio generation

feat: add create_voice_dropdown() widget factory

fix: gray out toggles and Generate Cards button until text generation completes

feat: add interactive parameter to toggle helper for disabled state in two-phase generation

feat: add media toggles and streaming progress bar

feat: scaffold repo structure with empty files and headers