Phase 4.F：微信截图分享 type=2 / 远端图分享 type=其它

按 msext gameController.m:637-678 字面行为，WechatShare 按 content.type
分发：
- type=1 → shareLink（已有）
- type=2 → captureScreenshot → JPEG 0.6 + thumb 0.4x → shareImage
- type=其它 → downloadRemote(URL) → JPEG 0.9 + thumb 0.4x → shareImage

新增：
- ImageProvider.scaledThumb(_:scale:)：等价 msext FuncPublic
  imageByScalingAndCroppingForSize 0.4x 缩放；微信 SDK setThumbImage:
  内部再压到 32KB
- WeChatManager.ShareImage 结构 + shareImage(_:scene:) 异步包装
  （WXImageObject + WXMediaMessage.setThumbImage，FIFO 串行复用 sharePending）

契约：与 type=1 一致，调成功 → sharesuccess 反向 callback（success/cancelled
都发）；errCode=-2 → cancelled；其它 errCode → failed。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ylgamehall/Source/SDK/WeChat/WeChatManager.swift

@@ -69,6 +69,19 @@ public final class WeChatManager: NSObject {
         }
     }
 
+    /// 图片分享载荷（type=2 截图 / type=3 远端图）。
+    /// imageData 是大图原始字节（JPEG 等），thumb 是缩略图源 — SDK
+    /// `setThumbImage:` 内部把 thumb 压到 32KB。
+    public struct ShareImage {
+        public let imageData: Data
+        public let thumb:     UIImage
+
+        public init(imageData: Data, thumb: UIImage) {
+            self.imageData = imageData
+            self.thumb = thumb
+        }
+    }
+
     /// 链接分享（FIFO 串行）。微信回包不携带配对 ID，连续调时按入队顺序消费。
     public func shareLink(_ link: ShareLink, scene: ShareScene) async throws {
         #if canImport(WechatOpenSDK)
@@ -97,6 +110,35 @@ public final class WeChatManager: NSObject {
         #endif
     }
 
+    /// 图片分享（FIFO 串行，复用 sharePending）。msext gameController.m:637-678
+    /// type=2 截图 / type=其它 远端图 共用同一条 WXImageObject + setThumbImage 路径。
+    public func shareImage(_ img: ShareImage, scene: ShareScene) async throws {
+        #if canImport(WechatOpenSDK)
+        try await withCheckedThrowingContinuation { (cont: CheckedContinuation<Void, Error>) in
+            sharePending.append(cont)
+
+            let media = WXImageObject()
+            media.imageData = img.imageData
+
+            let message = WXMediaMessage()
+            // 图片分享不需要 title / description（msext 字面：传 nil；这里传空串等价）
+            message.mediaObject = media
+            message.setThumbImage(img.thumb)
+
+            let req = SendMessageToWXReq()
+            req.bText = false
+            req.message = message
+            switch scene {
+            case .session:  req.scene = Int32(WXSceneSession.rawValue)
+            case .timeline: req.scene = Int32(WXSceneTimeline.rawValue)
+            }
+            WXApi.send(req)
+        }
+        #else
+        throw WeChatError.sdkNotLinked
+        #endif
+    }
+
     // MARK: - Internal: resolve callbacks
 
     fileprivate func resolveAuth(state: String, code: String?, errCode: Int) {