Add KeyValidation module for format-checking API keys before
attempting connections. Auto-strips whitespace, detects common
mistakes (e.g. pasting a Stripe publishable key), and returns
helpful error messages.
Inline field errors across all three entry points:
- Setup wizard: provider + Stripe keys
- Admin provider form: simplified to single Connect button
- Email settings: per-field errors instead of flash toasts
Also: plain text inputs for all API keys (not password fields),
accessible error states (aria-invalid, role=alert, thick border,
bold text), inner_block slot declaration on error component.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Extract Products.connect_provider/2 that tests the connection, fetches
shop_id, creates the record, and enqueues sync. Both the setup wizard
and the providers form now use this shared function instead of
duplicating the flow. Also makes the products empty state context-aware
(distinguishes "no provider" from "provider connected but no products").
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
