feat(seed): add WizaMart merchant with OMS trial and wizamart.com custom domain

Adds WizaMart S.à r.l. as a demo merchant with:
- OMS platform subscription (essential tier, 30-day trial)
- Custom domain wizamart.com linked to OMS platform
- Idempotent: safe to run multiple times

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/seed/seed_demo.py

@@ -153,6 +153,19 @@ DEMO_COMPANIES = [
         "business_address": "12 Rue du Web, Differdange, L-4501, Luxembourg",
         "tax_number": "LU45678901",
     },
+    {
+        "name": "WizaMart S.à r.l.",
+        "description": "Online marketplace for everyday essentials and home goods",
+        "owner_email": "alex.owner@wizamart.com",
+        "owner_password": "password123",  # noqa: SEC001
+        "owner_first_name": "Alex",
+        "owner_last_name": "Dupont",
+        "contact_email": "info@wizamart.com",
+        "contact_phone": "+352 567 890 123",
+        "website": "https://www.wizamart.com",
+        "business_address": "88 Route d'Arlon, Strassen, L-8008, Luxembourg",
+        "tax_number": "LU56789012",
+    },
 ]
 
 # Demo store configurations (linked to merchants by index)
@@ -245,6 +258,17 @@ DEMO_STORES = [
         "theme_preset": "modern",
         "custom_domain": None,
     },
+    # WizaMart store (OMS platform, custom domain)
+    {
+        "merchant_index": 4,  # WizaMart
+        "store_code": "WIZAMART",
+        "name": "WizaMart",
+        "subdomain": "wizamart",
+        "description": "Online marketplace for everyday essentials and home goods",
+        "theme_preset": "modern",
+        "custom_domain": "wizamart.com",
+        "custom_domain_platform": "oms",
+    },
 ]
 
 # Demo subscriptions (linked to merchants by index)
@@ -258,6 +282,8 @@ DEMO_SUBSCRIPTIONS = [
     {"merchant_index": 2, "platform_code": "oms", "tier_code": "business", "trial_days": 0},
     # LuxWeb Agency: Hosting (professional, active)
     {"merchant_index": 3, "platform_code": "hosting", "tier_code": "professional", "trial_days": 0},
+    # WizaMart: OMS (essential, trial)
+    {"merchant_index": 4, "platform_code": "oms", "tier_code": "essential", "trial_days": 30},
 ]
 
 # Demo team members (linked to merchants by index, assigned to stores by store_code)