Model Stammkapital/Grundkapital and Gesellschafter for the not-yet-needed legal forms

Mirrors the backend's new CompanySettings.shareCapital/generalPartners fields: rendered in the Impressum (AnbieterAngaben.tsx — new "Gesellschafter" section, Stammkapital line under Handelsregister, and the "Verantwortlich für den Inhalt" fallback now considers a general partner before falling back to sellerName) and wired into buildLegalFooterLines() for the invoice/email footer, same as registerCourt/registerNumber/managingDirector already were.

No visible change today (current legalForm is sole-proprietorship, neither field is set) — this is prep so a future legalForm change in company-settings updates the Impressum automatically instead of needing a manual Impressum edit at that point.

app/impressum/components/AnbieterAngaben.tsx

@@ -4,8 +4,8 @@ import type { CompanySettings } from "../../lib/payload";
 import type { TOCSection } from "../../components/SectionTOC";
 
 // Renders "Angaben zum Anbieter"/"Umsatzsteuer"/(conditionally)
-// "Handelsregister"/"Geschäftsführung"/"Verantwortlich für den Inhalt"
-// straight from company-settings, matching RichText.tsx's own heading/
+// "Handelsregister"/"Geschäftsführung"/"Gesellschafter"/"Verantwortlich für
+// den Inhalt" straight from company-settings, matching RichText.tsx's own heading/
 // paragraph classes so it reads as one continuous page with the CMS
 // content below it, not a bolted-on block. This used to be hand-typed
 // prose baked into the Impressum's richText (seed-legal-pages.ts on the
@@ -17,17 +17,21 @@ import type { TOCSection } from "../../components/SectionTOC";
 // already uses (see page.tsx's comment on that).
 //
 // Also closes a real compliance gap the old hand-typed text had: it never
-// showed Handelsregister/Geschäftsführung at all, even though
-// company-settings already models both (§37a HGB/§35a GmbHG) — those
-// fields just weren't wired into the Impressum. A sole proprietorship
-// (this shop's current legalForm) has neither, so neither section shows
-// today, but the moment that changes in company-settings, the Impressum
-// picks it up automatically instead of needing a second manual edit.
+// showed Handelsregister/Geschäftsführung/Gesellschafter/Stammkapital at
+// all, even though company-settings models all of them (§37a HGB/§35a
+// GmbHG/§80 AktG) — those fields just weren't wired into the Impressum. A
+// sole proprietorship (this shop's current legalForm) needs none of them,
+// so nothing extra shows today, but the moment legalForm changes in
+// company-settings (e.g. incorporating as a GmbH), the Impressum picks up
+// Handelsregister/Geschäftsführung/Stammkapital automatically — same for
+// generalPartners/"Gesellschafter" on an OHG/KG — instead of needing a
+// second manual edit here.
 export function anbieterAngabenHeadings(seller: CompanySettings | null): TOCSection[] {
   if (!seller) return [];
   const sections = ["Angaben zum Anbieter", "Umsatzsteuer"];
   if (seller.registerCourt && seller.registerNumber) sections.push("Handelsregister");
   if (seller.managingDirector) sections.push("Geschäftsführung");
+  if (seller.generalPartners && seller.generalPartners.length > 0) sections.push("Gesellschafter");
   sections.push("Verantwortlich für den Inhalt");
   return sections.map((title) => ({ id: headingId(title), title }));
 }
@@ -70,6 +74,7 @@ export function AnbieterAngaben({ seller }: { seller: CompanySettings }) {
           <Heading>Handelsregister</Heading>
           <P>{seller.registerCourt}</P>
           <P>{seller.registerNumber}</P>
+          {seller.shareCapital ? <P>Stammkapital: {seller.shareCapital.toLocaleString("de-DE")} €</P> : null}
         </>
       )}
 
@@ -80,8 +85,22 @@ export function AnbieterAngaben({ seller }: { seller: CompanySettings }) {
         </>
       )}
 
+      {seller.generalPartners && seller.generalPartners.length > 0 && (
+        <>
+          <Heading>Gesellschafter</Heading>
+          {seller.generalPartners.map((partner) => (
+            <P key={partner.name}>{partner.name}</P>
+          ))}
+        </>
+      )}
+
       <Heading>Verantwortlich für den Inhalt</Heading>
-      <P>{seller.managingDirector || seller.sellerName}</P>
+      {/* §18 Abs. 2 MStV wants a natural person — managingDirector first
+          (Kapitalgesellschaften), falling back to the first named
+          Gesellschafter (OHG/KG, no separate managingDirector field),
+          then finally sellerName itself (sole proprietorship/e.K.,
+          already a natural person's own name). */}
+      <P>{seller.managingDirector || seller.generalPartners?.[0]?.name || seller.sellerName}</P>
       <P>{seller.sellerStreet}</P>
       <P>
         {seller.sellerZip} {seller.sellerCity}