* refactor(settings): consolidate dialog guard flags and widget construction
The settings dialog grew the same work in several places. This gathers
the shared pieces into module helpers with no behavior change:
- _suppressed(): a context manager for the try/finally flag dance the
handlers used to open-code for _populating_models,
_processing_language_change, _simple_syncing, and _simple_driving.
The apply-guard handoff and the nested resync keep their explicit
save/restore because they do not fit a lexical block.
- _handlers_suppressed(): one name for the
"initializing or applying" check every handler repeated on entry.
- _set_no_show_all_visible(): the clear-flag / show / re-arm sequence
for rows created hidden, used by the second-language row and the
custom-shortcut row.
- _add_switch_row(), _combo_chrome(), _new_spin(),
_connect_picker_entry(): the repeated switch-row, tooltip +
scroll-guard, spin-button, and picker-entry wiring.
- _undownloaded_model_info() and _make_download_dialog(): the
per-engine download gate both apply paths carried verbatim.
Flags stay plain booleans and helpers stay module-level so existing
tests keep working unchanged.
* fix(settings): annotate download dialog builder and align visibility docs
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Co-authored-by: Jatin K Malik <jatinkrmalik@gmail.com>
