feat(demo): expand demo pet images and seed data with diverse breed showcase

Generated 16 diverse pet images for demo site using MiniMax image generation:
- Multiple dog breeds (Golden Retriever, Poodle, Labrador, Shih Tzu, Cocker Spaniel, Schnauzer, Maltese, Dachshund, Pomeranian)
- Professional grooming styles and poses
- Studio lighting for quality showcase

Updated seed.ts to create 9 demo pets with image references:
- Expands from single demo pet to diverse pet portfolio
- Images deployed to apps/web/public/demo-pets/
- Each pet has breed-accurate styling and professional grooming

This completes GRO-395 demo assets expansion using allocated MiniMax credits.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/web/src/BrandingContext.tsx

@@ -4,6 +4,7 @@ export interface Branding {
   businessName: string;
   primaryColor: string;
   accentColor: string;
+  logoUrl: string | null;
   logoBase64: string | null;
   logoMimeType: string | null;
 }
@@ -12,6 +13,7 @@ const DEFAULT_BRANDING: Branding = {
   businessName: "GroomBook",
   primaryColor: "#4f8a6f",
   accentColor: "#8b7355",
+  logoUrl: null,
   logoBase64: null,
   logoMimeType: null,
 };