feat(newsletter): slim inline newsletter form for footer

Add form-newsletter-inline internal component: compact email + button row
with a consent checkbox, dark-themed for the footer. Turnstile loads lazily
on first email focus (footer is on every page). Reuses /api/newsletter and
the newsletter validation. Wired into footer-main next to Kontakt & Community.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/lib/block-types.ts

@@ -469,7 +469,7 @@ export type CalendarBlockData = Omit<
 };
 
 /** Internal component block (_type: "internal_component"). */
-export type InternalComponentId = "form-contact" | "form-mitmachen" | "form-newsletter";
+export type InternalComponentId = "form-contact" | "form-mitmachen" | "form-newsletter" | "form-newsletter-inline";
 
 export interface InternalComponentBlockData {
   _type?: "internal_component";