Preferences and defaults

People rely on how SolidCraft behaves today. A change that makes users see or do something different out of the box is a change of a default.

The rule

• Keep the old behaviour reachable. Add a preference whose old value gives the old behaviour, and test that it still does.
• Fill in the PR template's Changes a default: line (pr-checks.yml fails a PR description without it, #6442; CONTRIBUTING.md, "Sending a change"):
  • Changes a default: no
  • Changes a default: yes - <what changes>, old behaviour kept behind preference <name>

Adding a preference

Settings live in the preference_settings! table in crates/ui-egui/src/prefs.rs: the field, its default, the page whose reset restores it, an optional accepted range for the control channel, and the form control. Add one row there.

• A new setting that changes nothing by default needs no yes on the line; one that changes what users see by default does.
• Give it a label and help text through the catalogs (skills/solidcraft-ui-text/SKILL.md).
• A reset on its page restores the default; fields left out of every page keep their values when defaults are restored.
• Control channel: ui.prefs {...} reads and sets preferences by name (docs/control-protocol.md).
• Test it in a UI scenario or a *_tests.rs file next to the setting (skills/solidcraft-tests/SKILL.md).