feat: 增强编辑动态功能，支持图片选择与处理

- 在EditFeedFeature中新增图片选择相关状态和动作，支持用户选择和处理最多9张图片。
- 在EditFeedView中集成ModernImageSelectionGrid组件，优化图片选择界面。
- 更新CreateFeedView以支持图片选择功能，提升用户体验。
- 实现图片处理逻辑，确保用户能够方便地添加和删除图片。

yana/Features/EditFeedFeature.swift

@@ -1,6 +1,7 @@
 import Foundation
 import ComposableArchitecture
 import SwiftUI
+import PhotosUI // 修正：导入PhotosUI
 
 @Reducer
 struct EditFeedFeature {
@@ -11,9 +12,24 @@ struct EditFeedFeature {
         var errorMessage: String? = nil
         var shouldDismiss: Bool = false
 
+        var selectedImages: [PhotosPickerItem] = []
+        var processedImages: [UIImage] = []
+        var canAddMoreImages: Bool {
+            processedImages.count < 9
+        }
+
         var canPublish: Bool {
             !content.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty && !isLoading
         }
+        // 手动实现Equatable，selectedImages只比较数量（PhotosPickerItem不支持Equatable）
+        static func == (lhs: State, rhs: State) -> Bool {
+            lhs.content == rhs.content &&
+            lhs.isLoading == rhs.isLoading &&
+            lhs.errorMessage == rhs.errorMessage &&
+            lhs.shouldDismiss == rhs.shouldDismiss &&
+            lhs.processedImages == rhs.processedImages &&
+            lhs.selectedImages.count == rhs.selectedImages.count
+        }
     }
 
     enum Action {
@@ -23,6 +39,11 @@ struct EditFeedFeature {
         case clearError
         case dismissView
         case clearDismissFlag
+        // 新增图片相关Action
+        case photosPickerItemsChanged([PhotosPickerItem])
+        case processPhotosPickerItems([PhotosPickerItem])
+        case updateProcessedImages([UIImage])
+        case removeImage(Int)
     }
 
     @Dependency(\.apiService) var apiService
@@ -83,6 +104,36 @@ struct EditFeedFeature {
             case .clearDismissFlag:
                 state.shouldDismiss = false
                 return .none
+            case .photosPickerItemsChanged(let items):
+                state.selectedImages = items
+                return .run { send in
+                    await send(.processPhotosPickerItems(items))
+                }
+            case .processPhotosPickerItems(let items):
+                let currentImages = state.processedImages
+                return .run { send in
+                    var newImages = currentImages
+                    for item in items {
+                        guard let data = try? await item.loadTransferable(type: Data.self),
+                              let image = UIImage(data: data) else { continue }
+                        if newImages.count < 9 {
+                            newImages.append(image)
+                        }
+                    }
+                    await MainActor.run {
+                        send(.updateProcessedImages(newImages))
+                    }
+                }
+            case .updateProcessedImages(let images):
+                state.processedImages = images
+                return .none
+            case .removeImage(let index):
+                guard index < state.processedImages.count else { return .none }
+                state.processedImages.remove(at: index)
+                if index < state.selectedImages.count {
+                    state.selectedImages.remove(at: index)
+                }
+                return .none
             }
         }
     }