feat(power): add reboot and shutdown syscalls and terminal commands

- REBOOT (0x1008): 8042 reset with PCI 0xCF9 fallback
- SHUTDOWN (0x1009): ACPI S5 writes to the common QEMU/Bochs/VBox
  PM1a control ports, then halt
- vpsdk.process.reboot()/shutdown()
- Terminal commands: reboot, shutdown (help updated)

Apps/Terminal/main.vp

@@ -345,7 +345,7 @@ export def _start() -> int:
             term.delete(0, -1)
         elif string.samestr(text, "help"):
             term.insert("File: ls cd cat pwd mkdir rm touch")
-            term.insert("Sys:  ver about sysinfo reboot")
+            term.insert("Sys:  ver about sysinfo reboot shutdown")
             term.insert("Util: echo clear help hexdump run runb")
         elif string.samestr(text, "ver"):
             term.insert("ViperOS Terminal v1.1")
@@ -370,7 +370,9 @@ export def _start() -> int:
         elif string.samestr(text, "sysinfo"):
             _cmd_sysinfo()
         elif string.samestr(text, "reboot"):
-            process.exit(0)
+            process.reboot()
+        elif string.samestr(text, "shutdown"):
+            process.shutdown()
         elif _startswith(text, "hexdump "):
             _cmd_hexdump(text + 8)
         elif _startswith(text, "run "):

VKernel/Kernel/intr/syscall.vp

@@ -9,6 +9,7 @@ import mm.mm as mm
 import paging.paging as paging
 import execrunner.elf as elf
 import drivers.devfs.devfs as devfs
+import asm
 
 
 # ============================================================================
@@ -46,14 +47,42 @@ enum Syscall:
     OPENDIR       = 0x1003  # TODO(linux)：openat(O_DIRECTORY) + getdents64
     READDIR       = 0x1004  # TODO(linux)：getdents64
     CLOSEDIR      = 0x1005  # TODO(linux)：close
-    LOAD_SO       = 0x1006  # TODO(用户层)：动态库加载下沉
-    SO_CALL1      = 0x1007  # TODO(用户层)：同上
+    LOAD_SO       = 0x1006  # TODO(userspace): dynamic library loading
+    SO_CALL1      = 0x1007  # TODO(userspace): dynamic library call
+    REBOOT        = 0x1008  # reboot()（本系统私有）
+    SHUTDOWN      = 0x1009  # shutdown()（本系统私有）
 
 define IA32_EFER  = 0xC0000080
 define IA32_STAR  = 0xC0000081
 define IA32_LSTAR = 0xC0000082
 define IA32_FMASK = 0xC0000084
 
+# Reset via the 8042 controller; PCI reset and halt are fallbacks.
+def power_reboot():
+    serial.puts("[power] reboot\n")
+    asm.cli()
+    for _ in range(1000):
+        if (asm.inb(0x64) & 0x02) == 0: break
+    asm.outb(0x64, 0xFE)
+    asm.outb(0xCF9, 0x02)
+    asm.io_wait()
+    asm.outb(0xCF9, 0x06)
+    while True:
+        asm.cli()
+        asm.hlt()
+
+# ACPI S5 on the common QEMU/Bochs/VirtualBox PM1a control ports.
+def power_shutdown():
+    serial.puts("[power] shutdown\n")
+    asm.cli()
+    asm.outw(0x604, 0x3400)
+    asm.outw(0x604, 0x2000)
+    asm.outw(0xB004, 0x2000)
+    asm.outw(0x4004, 0x3400)
+    while True:
+        asm.cli()
+        asm.hlt()
+
 def wrmsr(msr: uint32, val: uint64):
     lo: uint32 = uint32(val & 0xFFFFFFFF)
     hi: uint32 = uint32(val >> 32)
@@ -454,6 +483,12 @@ export def syscall_handler(num: uint64, arg1: uint64, arg2: uint64, arg3: uint64
         path_ptr: str = str(arg1)
         info_ptr: rawptr = rawptr(arg2)
         return uint64(STAT(path_ptr, info_ptr))
+    elif n == int(Syscall.REBOOT):
+        power_reboot()
+        return uint64(0)
+    elif n == int(Syscall.SHUTDOWN):
+        power_shutdown()
+        return uint64(0)
     elif n == int(Syscall.LOAD_SO):
         path_ptr_so: rawptr = rawptr(arg1)
         return LOAD_SO(path_ptr_so)

vpsdk/process.vp

@@ -4,6 +4,14 @@ from . import syscall as syscall
 def exit(code: int):
     syscall._syscall1(uint64(syscall.Syscall.EXIT), uint64(code))
 
+def reboot():
+    """Reset the machine."""
+    syscall._syscall0(uint64(syscall.Syscall.REBOOT))
+
+def shutdown():
+    """Power off the machine (ACPI S5 / QEMU PM1a)."""
+    syscall._syscall0(uint64(syscall.Syscall.SHUTDOWN))
+
 def thread_exit():
     """当前用户线程显式退出：内核回收其用户栈并标记线程结束（不返回）。"""
     syscall._syscall0(uint64(syscall.Syscall.THREAD_EXIT))

vpsdk/syscall.vp

@@ -30,8 +30,10 @@ enum Syscall:
     OPENDIR       = 0x1003  # TODO(linux)：openat(O_DIRECTORY) + getdents64
     READDIR       = 0x1004  # TODO(linux)：getdents64
     CLOSEDIR      = 0x1005  # TODO(linux)：close
-    LOAD_SO       = 0x1006  # TODO(用户层)：动态库加载下沉
-    SO_CALL1      = 0x1007  # TODO(用户层)：同上
+    LOAD_SO       = 0x1006  # TODO(userspace): dynamic library loading
+    SO_CALL1      = 0x1007  # TODO(userspace): dynamic library call
+    REBOOT        = 0x1008
+    SHUTDOWN      = 0x1009
 
 # ---- mmap 的 prot / flags（与内核 VKernel/intr/syscall.vp 及各 Linux 同名常量一致）----
 define PROT_NONE     = 0x0