feat: complete CMS v2 with Docker, Fischerei, Meetings, Verband modules + UX audit fixes

Major changes:
- Docker Compose: full Supabase stack (11 services) equivalent to supabase CLI
- Fischerei module: 16 DB tables, waters/species/stocking/catch books/competitions
- Sitzungsprotokolle module: meeting protocols, agenda items, task tracking
- Verbandsverwaltung module: federation management, member clubs, contacts, fees
- Per-account module activation via Modules page toggle
- Site Builder: live CMS data in Puck blocks (courses, events, membership registration)
- Public registration APIs: course signup, event registration, membership application
- Document generation: PDF member cards, Excel reports, HTML labels
- Landing page: real Com.BISS content (no filler text)
- UX audit fixes: AccountNotFound component, shared status badges, confirm dialog,
  pagination, duplicate heading removal, emoji→badge replacement, a11y fixes
- QA: healthcheck fix, API auth fix, enum mismatch fix, password required attribute

apps/web/app/api/healthcheck/route.ts

@@ -29,9 +29,10 @@ async function getSupabaseHealthCheck() {
     const { data, error } = await client
       .from('config')
       .select('billing_provider')
-      .single();
+      .limit(1)
+      .maybeSingle();
 
-    return !error && Boolean(data?.billing_provider);
+    return !error;
   } catch {
     return false;
   }