Fanta GPUI 0.2.0

The Variables screen now includes shared project/page mode selectors and selected-layer bindings, using the Fanta dropdowns and theme styles. Hosts provide the project title and handle typed mode and binding intents.

• Move mode selectors above the header and add a border to the search field.
• Preserve input deletion and navigation after an editor host reloads its keymap.
• Add padding to the alias picker's empty state and remove the duplicate binding-panel separator.
• Demonstrate first-variable creation with a default collection in Storybook.
• Remove the Import variables feature and VariablesAction::ImportVariablesRequested (breaking API change).

All 33 published workspace crates use version 0.2.0 with exact internal dependencies. Consumers should update the coordinated Fanta GPUI dependencies together.