docs(design): sync design guidance with the shipped system + new Stripe mark (#1211)

* docs(design): sync design guidance with the shipped frame-layout system

The design-scan skills and workflow predate the 2026-07 UI migration; they
delegated to .claude/rules/design.md but their inline checklists knew nothing
of the locked conventions, so scans could not flag violations of frame layout,
one-line rows, chips-as-exceptions or .attn. This adds the conventions to
scout-design, loop-design-scan, the /create-ticket design prompt and the
design-scan workflow contract.

design.md itself gets the two post-migration decisions it was missing: the
fiscal-year primitive is FyPicker (ContextPicker chip-dropdown, convention 8),
not the legacy FiscalYearSelector, and the founder-chosen Fonster settings
language (flat hairline rows, switches, dirty-only sticky save bar, 920x680
modal, replaceState tab switching) is now convention 15.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(import): swap the Stripe chip to the current parallelogram mark

Replaces the pre-rebrand Stripe wordmark svg with the current white-on-purple
parallelogram icon (same asset the website repo uses). stripe.svg had exactly
one reference; it is removed rather than left orphaned.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

app/(dashboard)/import/page.tsx

@@ -2098,7 +2098,7 @@ export default function ImportPage() {
                   <ImportRow
                     title={t('stripe_title')}
                     sub={t('stripe_description')}
-                    chips={<LogoChip src="/logos/stripe.svg" name="Stripe" />}
+                    chips={<LogoChip src="/logos/stripeicon.jpeg" name="Stripe" />}
                     disabled={stripeDisabled}
                     onClick={() => setMode('stripe')}
                   />