Feature: Add MCP device management-control tools (kill/window/service/power)

Add P7 management-control tools behind a single McpManage flag (plus
McpReadonly=0): kill_process, operate_window, control_service and
power_action. The write tools run a ready->confirm lifecycle on their
sub-connection, using a new followUp/followUpSent field to tell the two
arrivals of the same TOKEN_*LIST apart; the write command and the follow-up
refresh command go out as two separate Send2Client calls, with a new
WaitSendIdle() (context.h / Server.h) draining the outbound buffer in between
so the same buffer is never WSASend'd concurrently.

McpSettingsDlg gains a "management operations" checkbox (IDC_MCP_MANAGE), the
main toolbar gains an MCP entry button, and en/de/zh-TW strings are synced.
power_action is fire-and-forget over the main connection (no confirmation).

Verified end-to-end against a real Windows 10/VMware client: kill_process
returns remaining:[] and operate_window/control_service return ok:true with
their confirm packet arriving after an HTTP split. Verification surfaced a
prerequisite parser bug, fixed separately in a72e6eb, where HeaderParser
latched m_bShouldUnmask FALSE on HTTP continuation chunks and dropped the
confirm packet.

Co-Authored-By: deepseek-v4-pro

server/2015Remote/lang/en_US.ini

@@ -1990,18 +1990,20 @@ MCP
 端口需为 1-65535 的数字=Port must be a number between 1 and 65535
 Token 不能为空=Token cannot be empty
 MCP 设置已保存。=MCP settings saved.
-启用/端口/绑定地址/Token/只读/白名单/持久终端/远程控制/文件传输的改动需重启程序生效。=Changes to enable/port/bind address/token/read-only/whitelist/persistent terminal/remote control/file transfer take effect after restart.
+启用/端口/绑定地址/Token/只读/白名单/持久终端/远程控制/文件传输/管理操作的改动需重启程序生效。=Changes to enable/port/bind address/token/read-only/whitelist/persistent terminal/remote control/file transfer/management operations take effect after restart.
 只读模式（禁命令执行）=Read-only mode (disable command execution)
 命令白名单=Command whitelist
 MCP命令执行=MCP command execution
 启用持久终端（全命令，无白名单）=Enable persistent terminal (full commands, no whitelist)
-持久终端与远程控制仅在只读模式关闭时生效。=Persistent terminal and remote control take effect only when read-only mode is off.
+持久终端、远程控制与管理操作仅在只读模式关闭时生效。=Persistent terminal, remote control and management operations take effect only when read-only mode is off.
 MCP持久终端=MCP persistent terminal
 MCP远程控制=MCP remote control
 MCP文件传输=MCP file transfer
+MCP管理操作=MCP management operation
 Token=Token
 启用远程控制（AI 操控桌面）=Enable remote control (AI controls the desktop)
 启用文件传输（download_file）=Enable file transfer (download_file)
+启用管理操作（进程/窗口/服务/电源）=Enable management operations (process/window/service/power)
 第 %d 个钱包地址不合法!=Wallet address #%d is invalid!
 %d 新连接\r\n=%d New connection\r\n
 %d 本地连接断开\r\n=%d Local connection closed\r\n