Add key handling for ConfigureDates (space toggle components) and
DefineFormulas (n new, d delete, text input mode) wizard steps.
Render date component toggles, formula list with input area, and
sample formulas derived from detected measures.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
ImportPipeline holds all data and logic (raw JSON, records, proposals,
model_name, build_model). ImportWizard wraps it with UI-only state
(step, cursor, message). Rename WizardState → WizardStep throughout.
Headless import in dispatch.rs now constructs ImportPipeline directly.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>