docs: 完善安装指南并增强启动脚本功能

- 扩展 README.md 中的安装说明，增加环境要求、详细步骤和常见问题排查
- 重写 start.bat 脚本，支持参数化配置并添加多重回退机制
- 优化开发服务器启动流程，提升不同环境下的兼容性

start.bat

@@ -1 +1,59 @@
-npm run docs:dev -- --host 0.0.0.0
+@echo off
+setlocal ENABLEDELAYEDEXPANSION
+
+REM Usage:
+REM   start.bat [host] [port]
+REM Examples:
+REM   start.bat                -> try 0.0.0.0:4567, fallback to localhost and 5173
+REM   start.bat local 8080     -> localhost:8080
+REM   start.bat lan 4567       -> 0.0.0.0:4567
+
+set HOST=%~1
+if "%HOST%"=="" set HOST=0.0.0.0
+if /I "%HOST%"=="lan" set HOST=0.0.0.0
+if /I "%HOST%"=="local" set HOST=localhost
+
+set PORT=%~2
+if "%PORT%"=="" set PORT=4567
+set FALLBACK_PORT=5173
+
+echo [Start] VuePress dev on host %HOST% port %PORT%
+call npx vuepress@2.0.0-rc.24 dev docs --host %HOST% --port %PORT%
+if %ERRORLEVEL% EQU 0 goto success
+
+REM Fallback 1: switch to localhost same port
+if NOT "%HOST%"=="localhost" (
+  echo [Fallback] switch to localhost on same port %PORT%...
+  call npx vuepress@2.0.0-rc.24 dev docs --host localhost --port %PORT%
+  if %ERRORLEVEL% EQU 0 goto success
+)
+
+REM Fallback 2: clean cache and use localhost on fallback port
+if NOT "%PORT%"=="%FALLBACK_PORT%" (
+  echo [Fallback] clean cache and start on localhost:%FALLBACK_PORT%...
+  call npx vuepress@2.0.0-rc.24 dev docs --clean-cache --clean-temp --host localhost --port %FALLBACK_PORT%
+  if %ERRORLEVEL% EQU 0 (
+    set HOST=localhost
+    set PORT=%FALLBACK_PORT%
+    goto success
+  )
+)
+
+REM Fallback 3: try another common port
+set ALT_PORT=8080
+if NOT "%PORT%"=="%ALT_PORT%" (
+  echo [Fallback] try localhost:%ALT_PORT%...
+  call npx vuepress@2.0.0-rc.24 dev docs --host localhost --port %ALT_PORT%
+  if %ERRORLEVEL% EQU 0 (
+    set HOST=localhost
+    set PORT=%ALT_PORT%
+    goto success
+  )
+)
+
+echo [Error] Failed to start dev server. Please check firewall or port usage.
+exit /b 1
+
+:success
+echo [Ready] Open http://localhost:%PORT%/ (or http://%HOST%:%PORT%/ if accessible)
+exit /b 0