feat: restructure repo for collaboration + add desktop app source

- Reorganize project: clean structure (portable/ u-claw-app/ usb-scripts/ website/)
- Move docs into website/, rename uclaw-scripts to usb-scripts
- Add u-claw-app/ Electron desktop source code
- Add portable/setup.sh: one-command dev environment setup
- Add portable/SkillHub.html: skill marketplace page
- Update README: dev guide, contribution workflow, project structure
- Update .gitignore: exclude runtime binaries and build artifacts
- Expand China install guide: npm mirrors, detailed onboard wizard

usb-scripts/Windows-Install.bat

@@ -0,0 +1,74 @@
+@echo off
+chcp 65001 >/dev/null 2>&1
+title U-Claw - Extract and Launch
+
+echo.
+echo   ========================================
+echo     U-Claw v1.1
+echo     Extract and Launch (Windows)
+echo   ========================================
+echo.
+
+set "SCRIPT_DIR=%~dp0"
+set "ARCHIVE=%SCRIPT_DIR%U-Claw.tar.gz"
+set "INSTALL_DIR=%SCRIPT_DIR%U-Claw"
+
+REM Check archive
+if not exist "%ARCHIVE%" (
+    echo   [ERROR] U-Claw.tar.gz not found
+    echo   Please ensure this script and the archive are in the same directory
+    echo.
+    pause
+    exit /b 1
+)
+
+REM Check if already extracted
+if exist "%INSTALL_DIR%\app\core\node_modules" (
+    echo   U-Claw already extracted at: %INSTALL_DIR%
+    echo.
+    echo   [1] Launch directly (skip extract)
+    echo   [2] Re-extract (overwrite)
+    echo.
+    set /p choice="  Choose [1/2, default 1]: "
+    if "%choice%"=="2" (
+        echo.
+        echo   Re-extracting...
+        rmdir /s /q "%INSTALL_DIR%" >/dev/null 2>&1
+    ) else (
+        echo.
+        echo   Launching...
+        goto :start
+    )
+)
+
+REM Extract
+echo.
+echo   Extracting U-Claw to: %INSTALL_DIR%
+echo   This may take a few minutes...
+echo.
+
+where tar >/dev/null 2>&1
+if %errorlevel%==0 (
+    cd /d "%SCRIPT_DIR%"
+    tar xzf "%ARCHIVE%"
+    if %errorlevel% neq 0 (
+        echo   Extract failed! Please extract U-Claw.tar.gz manually
+        pause
+        exit /b 1
+    )
+) else (
+    echo   tar not available. Please extract U-Claw.tar.gz manually
+    echo   using 7-Zip or WinRAR to this directory.
+    pause
+    exit /b 1
+)
+
+echo   Extract complete!
+echo.
+
+:start
+echo   Starting OpenClaw...
+echo.
+
+cd /d "%INSTALL_DIR%"
+call "%INSTALL_DIR%\Windows-Start.bat"