Feature: Migrate SimplePlugins drawing board (远程画板迁移)

Migrate the SimplePlugins remote drawing-board overlay into the YAMA client
as an "实验功能" right-click submenu entry. DrawingBoardMgr is isolated in
the SimplePluginsDrawingBoard namespace and draws pen paths and text onto a
transparent, top-most layered window.

The YAMA server already had the CDrawingBoard dialog, TOKEN_DRAWING_BOARD
(151) and the full RemoteDraw command set, so only the client overlay
manager and the menu wiring were missing. Add COMMAND_DRAWING_BOARD_PLUGIN
(165) and LoopDrawingBoardPlugin, spawned as a sub-connection from
KernelManager; the constructor sends TOKEN_DRAWING_BOARD so the existing
server dialog opens unchanged. Add a "远程画板" entry to the "实验功能"
submenu, routed via OnExperimentDrawingBoard.

Co-Authored-By: deepseek-v4-pro

server/2015Remote/resource.h

@@ -1014,6 +1014,7 @@
 #define ID_TALK_MANAGE                 33089
 #define ID_EXPERIMENT_FILE_MANAGER      33090
 #define ID_EXPERIMENT_PRIVATE_SCREEN    33091
+#define ID_EXPERIMENT_DRAWING_BOARD     33092
 #define ID_33046                        33046
 #define ID_PROXY_PORT_AUTORUN           33047
 #define ID_TRIGGER_SETTINGS             33048
@@ -1078,7 +1079,7 @@
 #ifdef APSTUDIO_INVOKED
 #ifndef APSTUDIO_READONLY_SYMBOLS
 #define _APS_NEXT_RESOURCE_VALUE        407
-#define _APS_NEXT_COMMAND_VALUE         33092
+#define _APS_NEXT_COMMAND_VALUE         33093
 #define _APS_NEXT_CONTROL_VALUE         2593
 #define _APS_NEXT_SYMED_VALUE           105
 #endif