Remove Add Transaction feature and clean all related code

Deleted files:
- AddTransactionView.swift
- TransactionRepository.swift
- Transaction+CoreDataClass.swift

Cleaned files:
- SourceDetailViewModel: removed transactions published property,
  showingAddTransaction flag, transactionRepository dependency,
  addTransaction() and deleteTransaction() methods
- SourceDetailView: removed transactionsSection, TransactionRow struct,
  Add Transaction button from quickActions, sheet presentation
- InvestmentSource+CoreDataClass: removed transactions NSManaged property,
  transactionsArray, totalInvested, totalDividends, totalFees computed
  properties, and all transaction Core Data accessors
- SettingsViewModel: removed "Transaction" from resetAllData entity list
- SampleDataService: removed transactionRepository and sample transaction

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

PortfolioJournal/Models/CoreData/InvestmentSource+CoreDataClass.swift

@@ -16,7 +16,6 @@ public class InvestmentSource: NSManagedObject, Identifiable {
     @NSManaged public var category: Category?
     @NSManaged public var account: Account?
     @NSManaged public var snapshots: NSSet?
-    @NSManaged public var transactions: NSSet?
     @NSManaged public var asset: Asset?
 
     public override func awakeFromInsert() {
@@ -104,13 +103,6 @@ extension InvestmentSource {
         snapshots?.count ?? 0
     }
 
-    /// Returns transactions sorted by date descending
-    /// Performance note: This sorts on every call. For repeated access, cache the result.
-    var transactionsArray: [Transaction] {
-        let set = transactions as? Set<Transaction> ?? []
-        return set.sorted { $0.date > $1.date }
-    }
-
     var frequency: NotificationFrequency {
         NotificationFrequency(rawValue: notificationFrequency) ?? .monthly
     }
@@ -168,37 +160,6 @@ extension InvestmentSource {
         }
     }
 
-    /// Performance: Iterates transactions directly without sorting
-    var totalInvested: Decimal {
-        guard let set = transactions as? Set<Transaction> else { return Decimal.zero }
-        return set.reduce(Decimal.zero) { result, transaction in
-            let amount = transaction.decimalAmount
-            switch transaction.transactionType {
-            case .buy:
-                return result + amount
-            case .sell:
-                return result - amount
-            default:
-                return result
-            }
-        }
-    }
-
-    /// Performance: Iterates transactions directly without sorting
-    var totalDividends: Decimal {
-        guard let set = transactions as? Set<Transaction> else { return Decimal.zero }
-        return set.reduce(Decimal.zero) { result, transaction in
-            transaction.transactionType == .dividend ? result + transaction.decimalAmount : result
-        }
-    }
-
-    /// Performance: Iterates transactions directly without sorting
-    var totalFees: Decimal {
-        guard let set = transactions as? Set<Transaction> else { return Decimal.zero }
-        return set.reduce(Decimal.zero) { result, transaction in
-            transaction.transactionType == .fee ? result + transaction.decimalAmount : result
-        }
-    }
 }
 
 // MARK: - Account Scheduling
@@ -233,15 +194,4 @@ extension InvestmentSource {
     @objc(removeSnapshots:)
     @NSManaged public func removeFromSnapshots(_ values: NSSet)
 
-    @objc(addTransactionsObject:)
-    @NSManaged public func addToTransactions(_ value: Transaction)
-
-    @objc(removeTransactionsObject:)
-    @NSManaged public func removeFromTransactions(_ value: Transaction)
-
-    @objc(addTransactions:)
-    @NSManaged public func addToTransactions(_ values: NSSet)
-
-    @objc(removeTransactions:)
-    @NSManaged public func removeFromTransactions(_ values: NSSet)
 }

PortfolioJournal/Models/CoreData/Transaction+CoreDataClass.swift

@@ -1,75 +0,0 @@
-import Foundation
-import CoreData
-
-@objc(Transaction)
-public class Transaction: NSManagedObject, Identifiable {
-    @nonobjc public class func fetchRequest() -> NSFetchRequest<Transaction> {
-        return NSFetchRequest<Transaction>(entityName: "Transaction")
-    }
-
-    @NSManaged public var id: UUID
-    @NSManaged public var date: Date
-    @NSManaged public var type: String
-    @NSManaged public var shares: NSDecimalNumber?
-    @NSManaged public var price: NSDecimalNumber?
-    @NSManaged public var amount: NSDecimalNumber?
-    @NSManaged public var notes: String?
-    @NSManaged public var createdAt: Date
-    @NSManaged public var source: InvestmentSource?
-
-    public override func awakeFromInsert() {
-        super.awakeFromInsert()
-        id = UUID()
-        createdAt = Date()
-        date = Date()
-        type = TransactionType.buy.rawValue
-    }
-}
-
-enum TransactionType: String, CaseIterable, Identifiable {
-    case buy
-    case sell
-    case dividend
-    case fee
-    case transfer
-
-    var id: String { rawValue }
-
-    var displayName: String {
-        switch self {
-        case .buy: return "Buy"
-        case .sell: return "Sell"
-        case .dividend: return "Dividend"
-        case .fee: return "Fee"
-        case .transfer: return "Transfer"
-        }
-    }
-
-    var isInvestmentFlow: Bool {
-        self == .buy || self == .sell
-    }
-}
-
-// MARK: - Computed Properties
-
-extension Transaction {
-    var decimalShares: Decimal {
-        shares?.decimalValue ?? Decimal.zero
-    }
-
-    var decimalPrice: Decimal {
-        price?.decimalValue ?? Decimal.zero
-    }
-
-    var decimalAmount: Decimal {
-        if let amount = amount?.decimalValue, amount != 0 {
-            return amount
-        }
-        return decimalShares * decimalPrice
-    }
-
-    var transactionType: TransactionType {
-        TransactionType(rawValue: type) ?? .buy
-    }
-}
-

PortfolioJournal/Models/MonthlySummary.swift

@@ -15,6 +15,12 @@ struct MonthlySummary {
         return NSDecimalNumber(decimal: netPerformance / base).doubleValue * 100
     }
 
+    var formattedMonthYear: String {
+        let formatter = DateFormatter()
+        formatter.dateFormat = "MMMM yyyy"
+        return formatter.string(from: startDate)
+    }
+
     var formattedStartingValue: String {
         CurrencyFormatter.format(startingValue, style: .currency, maximumFractionDigits: 0)
     }