feat: add Linux support, pnpm build fixes, and website updates

- Add Linux x64 platform support (运行.sh, build script, docs)
- Fix pnpm-first build logic across all launcher scripts
- Update website: 3→4 platforms, Linux in 3-step guide
- Update docs: Qwen free tier, StepFun model, 省钱提示
- Fix .gitignore for build artifacts

uclaw-scripts/运行.command

@@ -34,6 +34,7 @@ fi
 
 NODE_BIN="$NODE_DIR/bin/node"
 NPM_BIN="$NODE_DIR/bin/npm"
+PNPM_BIN="$NODE_DIR/bin/pnpm"
 
 if [ ! -f "$NODE_BIN" ]; then
     echo -e "  ${RED}错误: 找不到 Node.js 运行环境${NC}"
@@ -49,6 +50,21 @@ echo ""
 
 export PATH="$NODE_DIR/bin:$PATH"
 
+ensure_pnpm() {
+    if [ -x "$PNPM_BIN" ]; then
+        return 0
+    fi
+
+    echo -e "  ${YELLOW}缺少 pnpm，正在补充安装...${NC}"
+    "$NPM_BIN" install -g pnpm --registry=https://registry.npmmirror.com 2>&1
+
+    if [ ! -x "$PNPM_BIN" ]; then
+        echo -e "  ${RED}错误: pnpm 安装失败，无法继续构建${NC}"
+        read -p "  按回车键退出..."
+        exit 1
+    fi
+}
+
 # 检查依赖
 if [ ! -d "$OPENCLAW_DIR/node_modules" ]; then
     echo -e "  ${YELLOW}首次运行，正在安装依赖...${NC}"
@@ -65,7 +81,8 @@ fi
 if [ ! -d "$OPENCLAW_DIR/dist" ]; then
     echo -e "  ${YELLOW}首次运行，正在构建...${NC}"
     cd "$OPENCLAW_DIR"
-    "$NODE_BIN" "$NPM_BIN" run build 2>&1
+    ensure_pnpm
+    "$PNPM_BIN" run build 2>&1
     if [ ! -d "$OPENCLAW_DIR/dist" ]; then
         echo -e "  ${RED}构建失败，请检查错误信息${NC}"
         read -p "  按回车键退出..."