feat: URL deduplication for media library and queue

- On load: merge duplicate URLs (keep first, merge tags/liked/position)
- addItem: check queue for existing URL, show toast if duplicate
- addItemNoPlay: skip if URL already in queue
- Add hasItem(url:) helper
- Playlist references updated when merging duplicates

Sources/MediaLibrary.swift

@@ -122,9 +122,62 @@ final class MediaLibrary: ObservableObject {
               let store = try? JSONDecoder().decode(LibraryStore.self, from: data) else { return }
         items = store.items
         playlists = store.playlists
+        deduplicateItems()
         rebuildIndexes()
     }
     
+    /// 合并URL重复条目：保留首次出现的条目，删除后续重复，播放列表引用合并
+    private func deduplicateItems() {
+        var seen: [String: String] = [:]  // url → first itemID
+        var firstOccurrence: [String: Int] = [:]  // url → first index
+        var toRemove: Set<String> = []
+        
+        for (i, item) in items.enumerated() {
+            if let existingID = seen[item.url] {
+                // 重复：合并元数据到首次出现的条目
+                toRemove.insert(item.id)
+                if let firstIdx = firstOccurrence[item.url] {
+                    // 合并：保留更好的名字、tags、like状态、播放位置
+                    if items[firstIdx].lastPosition < item.lastPosition {
+                        items[firstIdx].lastPosition = item.lastPosition
+                    }
+                    if !items[firstIdx].liked && item.liked {
+                        items[firstIdx].liked = true
+                    }
+                    // 合并tags
+                    for tag in item.tags where !items[firstIdx].tags.contains(tag) {
+                        items[firstIdx].tags.append(tag)
+                    }
+                    items[firstIdx].tags.sort()
+                    // 合并播放列表引用：将重复ID替换为首条ID
+                    for p in playlists.indices {
+                        if let pos = playlists[p].itemIDs.firstIndex(of: item.id) {
+                            if !playlists[p].itemIDs.contains(existingID) {
+                                playlists[p].itemIDs[pos] = existingID
+                            } else {
+                                playlists[p].itemIDs.remove(at: pos)
+                            }
+                        }
+                    }
+                }
+            } else {
+                seen[item.url] = item.id
+                firstOccurrence[item.url] = i
+            }
+        }
+        
+        if !toRemove.isEmpty {
+            items.removeAll { toRemove.contains($0.id) }
+            NSLog("[MiniPlayer] Deduplicated \(toRemove.count) items")
+            save()
+        }
+    }
+    
+    /// URL是否存在
+    func hasItem(url: String) -> Bool {
+        urlIndex[url] != nil
+    }
+    
     /// 异步保存 — 不阻塞主线程，M3U几千条数据不卡UI
     private var saveTask: DispatchWorkItem?
     

Sources/PlayerBridge.swift

@@ -494,8 +494,14 @@ final class PlayerBridge: ObservableObject {
     }
     
     func addItem(url: URL, name: String, type: String) {
-        // 自动入库
-        let libItem = library.addItem(url: url.absoluteString, name: name, type: type)
+        let urlString = url.absoluteString
+        // 检查队列是否已有相同URL
+        if queue.contains(where: { $0.url.absoluteString == urlString }) {
+            showToast("⚠️ \(name) already in queue")
+            return
+        }
+        // 自动入库（库内已自动去重）
+        let libItem = library.addItem(url: urlString, name: name, type: type)
         queue.append(MediaItem(id: UUID().uuidString, url: url, name: name,
                                 mediaType: type, libraryID: libItem.id))
         if queue.count == 1 { playIndex(0) }
@@ -607,6 +613,10 @@ final class PlayerBridge: ObservableObject {
     
     /// 添加到队列但不播放（用于批量加入）
     func addItemNoPlay(url: URL, name: String, type: String, libraryID: String? = nil) {
+        // 队列去重
+        if queue.contains(where: { $0.url.absoluteString == url.absoluteString }) {
+            return
+        }
         queue.append(MediaItem(id: UUID().uuidString, url: url, name: name,
                                 mediaType: type, libraryID: libraryID))
         // 如果队列为空则自动播放第一个