fix: use xsct (not Vivado) for JTAG check + normalize COM>=10 ports on Windows

**JTAG check**: Switch from Vivado to xsct
- xsct is already proven to work (JTAG reboot succeeds)
- Much lighter than Vivado (no GUI infrastructure / open_hw_manager)
- Uses -eval inline TCL: connect; targets; disconnect; quit
- Removes dead tempfile/Path/os imports

**Windows COM port**: Add normalize_port() to serial_monitor.py
- COM ports >= 10 require NT namespace prefix (\.\COM11)
- Without it: PermissionError(13, '拒绝访问。')
- Applied at all 7 call sites: serial_monitor (5), reboot_manager, widgets

src/serial_monitor.py

@@ -7,8 +7,10 @@ Provides UartMonitor for continuous background monitoring.
 
 from __future__ import annotations
 
+import platform
 import re
 import threading
+import time
 from dataclasses import dataclass
 from typing import Callable
 
@@ -16,6 +18,26 @@ import serial
 import serial.tools.list_ports
 
 
+def normalize_port(port: str) -> str:
+    """Normalize a serial port name for the current platform.
+
+    On Windows, COM ports numbered >= 10 require the NT namespace
+    prefix (\\\\.\\COM11). Without it, CreateFile fails with
+    'Access denied' or 'file not found'.
+
+    Args:
+        port: Raw port name from config or detection.
+
+    Returns:
+        Normalized port name suitable for serial.Serial().
+    """
+    if platform.system() == "Windows":
+        match = re.match(r"^COM(\d+)$", port, re.IGNORECASE)
+        if match and int(match.group(1)) >= 10:
+            return rf"\\.\{port}"
+    return port
+
+
 @dataclass
 class BootInfo:
     """Parsed information extracted from Zynq boot output."""
@@ -168,7 +190,7 @@ def check_uart_available(
 
     # 3. Try to open and read
     try:
-        with serial.Serial(port, baudrate, timeout=timeout) as ser:
+        with serial.Serial(normalize_port(port), baudrate, timeout=timeout) as ser:
             ser.reset_input_buffer()
             lines: list[str] = []
             while ser.in_waiting:
@@ -206,7 +228,7 @@ def read_serial_stream(
         serial.SerialException: If the port cannot be opened.
     """
     lines: list[str] = []
-    with serial.Serial(port, baudrate, timeout=timeout) as ser:
+    with serial.Serial(normalize_port(port), baudrate, timeout=timeout) as ser:
         # Clear any pending data
         ser.reset_input_buffer()
         while ser.in_waiting:
@@ -242,8 +264,7 @@ def test_serial_version(
     import serial
 
     try:
-        with serial.Serial(port, baudrate, timeout=timeout) as ser:
-            # Clear buffers
+        with serial.Serial(normalize_port(port), baudrate, timeout=timeout) as ser:
             ser.reset_input_buffer()
             ser.reset_output_buffer()
 
@@ -384,7 +405,7 @@ class UartMonitor:
 
         # Quick port check before starting thread
         try:
-            test_ser = serial.Serial(self._port, self._baudrate, timeout=1)
+            test_ser = serial.Serial(normalize_port(self._port), self._baudrate, timeout=1)
             test_ser.close()
         except serial.SerialException as e:
             if self.on_error:
@@ -411,7 +432,7 @@ class UartMonitor:
         """Main read loop running in background thread."""
         try:
             ser = serial.Serial(
-                self._port,
+                normalize_port(self._port),
                 self._baudrate,
                 timeout=self._timeout,
             )