feat: add iOS support and harden receipt scanning

app/ios/ScanReceipts/Models/Receipt.swift

@@ -0,0 +1,148 @@
+import Foundation
+
+/// Mirrors `ProcessedReceipt` (src/lib/schema/receipt.ts) exactly — this is
+/// the shape returned by `GET /api/receipts` and accepted by
+/// `POST /api/receipts`. Keep this file and that Zod schema in sync; when the
+/// web schema gains a field, add it here too rather than silently dropping it
+/// on decode (optional fields decode fine as `nil` when absent, so older
+/// receipts synced before a schema change won't crash the app).
+struct Receipt: Codable, Identifiable, Equatable {
+    let id: String
+    var projectId: String?
+    let imageHash: String
+    let originalFileName: String
+    let fileSizeBytes: Int
+    var previewUrl: String?
+    let createdAt: String
+    let updatedAt: String
+    var status: ReceiptStatus
+
+    var merchant: Merchant
+    var date: ReceiptDate
+    var documentType: DocumentType
+    var receiptNumber: String?
+    var currency: String
+    var totalAmount: AmountWithConfidence
+    var netAmount: Double?
+    var tipAmount: Double?
+    var taxBreakdown: [TaxBreakdownItem]
+    var lineItems: [LineItem]
+    var suggestedCategory: ReceiptCategory
+    var paymentMethod: PaymentMethod?
+    var hospitality: Hospitality?
+    var validation: Validation
+
+    /// Total actually paid: `totalAmount.value + tipAmount`. Mirrors
+    /// `grossWithTip()` on the backend — tip is deliberately excluded from
+    /// `totalAmount` there because VAT is never charged on it.
+    var grossWithTip: Double {
+        ((totalAmount.value + (tipAmount ?? 0)) * 100).rounded() / 100
+    }
+
+    struct Merchant: Codable, Equatable {
+        var name: String
+        var address: String?
+        var taxId: String?
+        var confidence: Double
+    }
+
+    struct ReceiptDate: Codable, Equatable {
+        var isoDate: String
+        var time: String?
+        var confidence: Double
+    }
+
+    struct AmountWithConfidence: Codable, Equatable {
+        var value: Double
+        var confidence: Double
+    }
+
+    struct TaxBreakdownItem: Codable, Equatable, Identifiable {
+        var ratePercent: Double
+        var taxAmount: Double
+        var netAmount: Double?
+        var id: String { "\(ratePercent)-\(taxAmount)" }
+    }
+
+    struct LineItem: Codable, Equatable, Identifiable {
+        var id = UUID()
+        var description: String
+        var quantity: Double
+        var price: Double
+        var unitPrice: Double?
+        var taxRate: Double?
+
+        enum CodingKeys: String, CodingKey {
+            case description, quantity, price, unitPrice, taxRate
+        }
+    }
+
+    struct Hospitality: Codable, Equatable {
+        var occasion: String?
+        var participants: String?
+    }
+
+    struct Validation: Codable, Equatable {
+        var isMathValid: Bool
+        var isDuplicateSuspected: Bool
+        var needsUserReview: Bool
+        var reviewField: String
+        var reviewReason: String?
+        var issues: [Issue]?
+        var userConfirmed: Bool?
+
+        struct Issue: Codable, Equatable {
+            var field: String
+            var severity: String
+            var message: String
+        }
+    }
+
+    enum ReceiptStatus: String, Codable {
+        case pending, processing, ready, needsReview = "needs_review", error
+    }
+
+    enum DocumentType: String, Codable, CaseIterable {
+        case kassenbon = "KASSENBON"
+        case rechnung = "RECHNUNG"
+        case tankbeleg = "TANKBELEG"
+        case bewirtungsbeleg = "BEWIRTUNGSBELEG"
+        case parkticket = "PARKTICKET"
+        case sonstiges = "SONSTIGES"
+    }
+
+    enum PaymentMethod: String, Codable, CaseIterable {
+        case bar = "BAR"
+        case ecKarte = "EC_KARTE"
+        case kreditkarte = "KREDITKARTE"
+        case ueberweisung = "UEBERWEISUNG"
+        case paypal = "PAYPAL"
+        case applePay = "APPLE_PAY"
+        case googlePay = "GOOGLE_PAY"
+        case sonstige = "SONSTIGE"
+    }
+
+    enum ReceiptCategory: String, Codable, CaseIterable {
+        case bewirtung = "Bewirtung"
+        case reisekosten = "Reisekosten & Hotel"
+        case tanken = "Tanken & KFZ"
+        case buerobedarf = "Bürobedarf & IT"
+        case verpflegungsmehraufwand = "Verpflegungsmehraufwand"
+        case material = "Material & Einkauf"
+        case sonstiges = "Sonstiges"
+    }
+}
+
+/// `GET /api/receipts` response envelope.
+struct ReceiptListResponse: Decodable {
+    let success: Bool
+    let receipts: [Receipt]
+    let count: Int
+}
+
+/// `POST /api/receipts` response envelope (batch upsert).
+struct ReceiptSyncResponse: Decodable {
+    let success: Bool
+    let syncedCount: Int?
+    let message: String?
+}