feat: add Android build target and improve Android compatibility

- Makefile: add build-android target to compile picoclaw and picoclaw-launcher for Android ARM64
- Makefile: output both binaries and copy as .so files for Android integration
- dns_noresolv: change default DNS servers to Alibaba (223.5.5.5) and Tencent (119.29.29.29)
- agent: skip exec tool initialization on Android (no shell available)

Makefile

@@ -165,6 +165,23 @@ build-linux-mipsle: generate
 	$(call PATCH_MIPS_FLAGS,$(BUILD_DIR)/$(BINARY_NAME)-linux-mipsle)
 	@echo "Build complete: $(BUILD_DIR)/$(BINARY_NAME)-linux-mipsle"
 
+## build-android: Build picoclaw + picoclaw-launcher for Android (ARM64)
+build-android: generate
+	@echo "Building $(BINARY_NAME) for Android (linux/arm64)..."
+	@mkdir -p $(BUILD_DIR)
+	GOOS=linux GOARCH=arm64 $(GO) build $(GOFLAGS) -ldflags "$(LDFLAGS)" -o $(BUILD_DIR)/$(BINARY_NAME)-linux-arm64 ./$(CMD_DIR)
+	@cp $(BUILD_DIR)/$(BINARY_NAME)-linux-arm64 $(BUILD_DIR)/libpicoclaw.so
+	@echo "Build complete: $(BUILD_DIR)/$(BINARY_NAME)-linux-arm64 -> libpicoclaw.so"
+	@echo ""
+	@echo "Building picoclaw-launcher for Android (linux/arm64)..."
+	@if [ ! -f web/backend/dist/index.html ]; then \
+		echo "Building frontend..."; \
+		cd web/frontend && pnpm install && pnpm build:backend; \
+	fi
+	GOOS=linux GOARCH=arm64 $(GO) build $(GOFLAGS) -ldflags "$(LDFLAGS)" -o $(BUILD_DIR)/picoclaw-launcher-linux-arm64 ./web/backend
+	@cp $(BUILD_DIR)/picoclaw-launcher-linux-arm64 $(BUILD_DIR)/libpicoclaw-web.so
+	@echo "Build complete: $(BUILD_DIR)/picoclaw-launcher-linux-arm64 -> libpicoclaw-web.so"
+
 ## build-pi-zero: Build for Raspberry Pi Zero 2 W (32-bit and 64-bit)
 build-pi-zero: build-linux-arm build-linux-arm64
 	@echo "Pi Zero 2 W builds: $(BUILD_DIR)/$(BINARY_NAME)-linux-arm (32-bit), $(BUILD_DIR)/$(BINARY_NAME)-linux-arm64 (64-bit)"

cmd/picoclaw/dns_noresolv.go

@@ -20,7 +20,8 @@ func init() {
 	// 例如: PICOCLAW_DNS_SERVER="8.8.8.8:53;1.1.1.1:53;223.5.5.5:53"
 	dnsEnv := os.Getenv("PICOCLAW_DNS_SERVER")
 	if dnsEnv == "" {
-		dnsEnv = "8.8.8.8:53;1.1.1.1:53"
+		// 默认使用阿里 DNS 和腾讯 DNS
+		dnsEnv = "223.5.5.5:53;119.29.29.29:53"
 	}
 
 	var dnsServers []string

pkg/agent/instance.go

@@ -83,12 +83,16 @@ func NewAgentInstance(
 		toolsRegistry.Register(tools.NewListDirTool(workspace, readRestrict, allowReadPaths))
 	}
 	if cfg.Tools.IsToolEnabled("exec") {
-		execTool, err := tools.NewExecToolWithConfig(workspace, restrict, cfg, allowReadPaths)
+		if isAndroid() {
-		if err != nil {
+			logger.InfoCF("agent", "Skipping exec tool on Android (no shell available)", nil)
-			logger.ErrorCF("agent", "Failed to initialize exec tool; continuing without exec",
-				map[string]any{"error": err.Error()})
 		} else {
-			toolsRegistry.Register(execTool)
+			execTool, err := tools.NewExecToolWithConfig(workspace, restrict, cfg, allowReadPaths)
+			if err != nil {
+				logger.ErrorCF("agent", "Failed to initialize exec tool; continuing without exec",
+					map[string]any{"error": err.Error()})
+			} else {
+				toolsRegistry.Register(execTool)
+			}
 		}
 	}
 
@@ -321,3 +325,11 @@ func expandHome(path string) string {
 	}
 	return path
 }
+
+// isAndroid 检测当前是否运行在 Android 环境中。
+// Android 上 GOOS=linux，无法通过 runtime.GOOS 区分，
+// 因此通过检查 Android 特有的 /system/build.prop 文件来判断。
+func isAndroid() bool {
+	_, err := os.Stat("/system/build.prop")
+	return err == nil
+}