feat(api): .NET 10 multi-tenant REST API

Full backend implementation:
- Multi-tenant cafe/restaurant management (menus, orders, tables, staff)
- POS order flow with ZarinPal and Snappfood payment integration
- OTP authentication via Kavenegar SMS
- QR digital menu with public discover/finder endpoints
- Customer loyalty, coupons, CRM
- PostgreSQL via EF Core, Redis for caching/sessions
- Background jobs, webhook handlers
- Full migration history

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

data/category-icon-presets.json

@@ -0,0 +1,46 @@
+{
+  "version": 2,
+  "styles": ["flat", "modern", "real", "minimal", "outline", "soft", "bold", "gradient", "pastel", "duotone"],
+  "presets": [
+    { "id": "drinks-hot", "kind": "drink" },
+    { "id": "drinks-cold", "kind": "drink" },
+    { "id": "drinks-tea", "kind": "drink" },
+    { "id": "drinks-juice", "kind": "drink" },
+    { "id": "drinks-milkshake", "kind": "drink" },
+    { "id": "drinks-alcohol", "kind": "drink" },
+    { "id": "drinks-beer", "kind": "drink" },
+    { "id": "breakfast", "kind": "food" },
+    { "id": "food-mains", "kind": "food" },
+    { "id": "food-fastfood", "kind": "food" },
+    { "id": "food-rice", "kind": "food" },
+    { "id": "pasta-pizza", "kind": "food" },
+    { "id": "dessert", "kind": "food" },
+    { "id": "ice-cream", "kind": "food" },
+    { "id": "bakery", "kind": "food" },
+    { "id": "salad", "kind": "food" },
+    { "id": "grill", "kind": "food" },
+    { "id": "seafood", "kind": "food" },
+    { "id": "snacks", "kind": "food" },
+    { "id": "snacks-sweet", "kind": "food" },
+    { "id": "appetizers", "kind": "food" },
+    { "id": "vegan", "kind": "food" },
+    { "id": "fruits", "kind": "food" },
+    { "id": "specials", "kind": "food" },
+    { "id": "chef-special", "kind": "food" },
+    { "id": "generic", "kind": "food" }
+  ],
+  "emojiGroups": [
+    "hotDrinks",
+    "coldDrinks",
+    "breakfast",
+    "mains",
+    "pastaPizza",
+    "desserts",
+    "salads",
+    "seafoodGrill",
+    "snacks",
+    "vegan",
+    "specials",
+    "general"
+  ]
+}