Refactor: Move FileManager to common, add macOS file management support

macos/ScreenHandler.mm

@@ -3,6 +3,8 @@
 #import "InputHandler.h"
 #import "../client/IOCPClient.h"
 #import "../common/commands.h"
+#import "../common/FileTransferV2.h"
+#import "../common/logger.h"
 #import "Permissions.h"
 #import <Cocoa/Cocoa.h>
 #import <chrono>
@@ -280,6 +282,72 @@ void ScreenHandler::OnReceive(uint8_t* data, ULONG size)
             }
             break;
 
+        case COMMAND_GET_FILE:
+            // Server requests file download: [cmd:1][targetDir\0][file1\0file2\0...\0]
+            // Use V2 protocol to upload files
+            {
+                if (size < 3) break;
+
+                // Parse target directory (GBK encoding)
+                const char* ptr = (const char*)(data + 1);
+                const char* end = (const char*)(data + size);
+                std::string targetDirGbk = ptr;
+                std::string targetDir = FileTransferV2::gbkToUtf8(targetDirGbk);
+                ptr += targetDirGbk.length() + 1;
+
+                // Parse file list
+                std::vector<std::string> files;
+                while (ptr < end && *ptr != '\0') {
+                    std::string fileGbk = ptr;
+                    files.push_back(FileTransferV2::gbkToUtf8(fileGbk));
+                    ptr += fileGbk.length() + 1;
+                }
+
+                // TODO: If no file list, get from clipboard (ClipboardHandler not implemented yet)
+
+                if (!files.empty() && !targetDir.empty()) {
+                    NSLog(@">>> COMMAND_GET_FILE: %zu files -> %s", files.size(), targetDir.c_str());
+
+                    // Use V2 protocol to send files
+                    IOCPClient* client = m_client;
+                    std::thread([files, targetDir, client]() {
+                        // Collect all files (expand directories)
+                        std::vector<std::string> allFiles;
+                        std::vector<std::string> rootCandidates;
+
+                        for (const auto& path : files) {
+                            struct stat st;
+                            if (stat(path.c_str(), &st) != 0) continue;
+
+                            if (S_ISDIR(st.st_mode)) {
+                                std::string dirPath = path;
+                                if (dirPath.back() != '/') dirPath += '/';
+                                size_t pos = dirPath.rfind('/', dirPath.length() - 2);
+                                std::string parentPath = (pos != std::string::npos) ? dirPath.substr(0, pos + 1) : dirPath;
+                                rootCandidates.push_back(parentPath);
+                                FileTransferV2::CollectFiles(dirPath, allFiles);
+                            } else {
+                                rootCandidates.push_back(path);
+                                allFiles.push_back(path);
+                            }
+                        }
+
+                        if (allFiles.empty()) {
+                            NSLog(@"*** No files to send");
+                            return;
+                        }
+
+                        std::string commonRoot = FileTransferV2::GetCommonRoot(rootCandidates);
+                        NSLog(@">>> Sending %zu files, root=%s", allFiles.size(), commonRoot.c_str());
+
+                        FileTransferV2::SendFilesV2(allFiles, targetDir, commonRoot, client, g_myClientID);
+                    }).detach();
+                } else {
+                    NSLog(@"*** COMMAND_GET_FILE: no files or empty target");
+                }
+            }
+            break;
+
         default:
             break;
     }