feat(strommix): variant system + wald palette + UX polish

Add full/compact variants, prominent share, source badge, big
negative-price banner with conditional disclaimer, cards-style
context row, fade-in animation, and remove em-dashes from
visible strings.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/lib/block-types.ts

@@ -337,6 +337,9 @@ export interface OrganisationsBlockData {
 export interface LiveStrommixBlockData {
   _type?: "live_strommix";
   _slug?: string;
+  /** `full` = card with argument + breakdown disclosure. `compact` = single
+   *  horizontal strip for sidebar / homepage placement. Default: `full`. */
+  variant?: "full" | "compact";
   intro_headline?: string;
   intro_text?: string;
   threshold_dunkelflaute?: number;
@@ -352,6 +355,11 @@ export interface LiveStrommixBlockData {
   argument_hoch?: string;
   enable_france_comparison?: boolean;
   disclaimer?: string;
+  /** Day-ahead price (€/MWh) below which `disclaimer` is rendered.
+   *  Default 10 — disclaimer about EEG-Vergütung at negative prices is
+   *  irrelevant at 130 €/MWh and gets hidden. Set very high (e.g. 9999)
+   *  to always show. */
+  disclaimer_threshold_eur_mwh?: number;
   /** Reference (resolved: { _slug, _type, ...page-fields } or just slug string). */
   explanation_page?: string | { _slug?: string; title?: string };
   layout?: BlockLayout;