fix: replace remaining hardcoded GOARCH=amd64 with arch-aware defaults

Five files still had hardcoded amd64 references:
- nomad-nodepool-apm/Makefile: GOARCH=amd64 → GOARCH=$(BUILD_ARCH)
- clickhouse/Makefile: --platform linux/amd64 → linux/$(BUILD_ARCH)
- dashboard-api/Makefile: --platform linux/amd64 → linux/$(BUILD_ARCH)
- docker-reverse-proxy/Makefile: --platform linux/amd64 → linux/$(BUILD_ARCH)
- smoketest/smoke_test.go: GOARCH=amd64 → runtime.GOARCH

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 2 people

packages/clickhouse/Makefile

@@ -33,7 +33,7 @@ migrate-local:
 
 .PHONY: build
 build:
-	@docker build --platform linux/amd64 --tag "$(CLICKHOUSE_MIGRATOR_IMAGE)" .
+	@docker build --platform linux/$(or $(BUILD_ARCH),$(shell go env GOARCH)) --tag "$(CLICKHOUSE_MIGRATOR_IMAGE)" .
 
 .PHONY: build-and-upload
 build-and-upload:build

packages/dashboard-api/Makefile

@@ -28,7 +28,7 @@ build:
 build-and-upload:
 		$(eval COMMIT_SHA := $(shell git rev-parse --short HEAD))
 		$(eval EXPECTED_MIGRATION_TIMESTAMP := $(expectedMigration))
-		@ docker build --platform linux/amd64 --tag $(IMAGE_REGISTRY) --push --build-arg COMMIT_SHA="$(COMMIT_SHA)" --build-arg EXPECTED_MIGRATION_TIMESTAMP="$(EXPECTED_MIGRATION_TIMESTAMP)"  -f ./Dockerfile ..
+		@ docker build --platform linux/$(or $(BUILD_ARCH),$(shell go env GOARCH)) --tag $(IMAGE_REGISTRY) --push --build-arg COMMIT_SHA="$(COMMIT_SHA)" --build-arg EXPECTED_MIGRATION_TIMESTAMP="$(EXPECTED_MIGRATION_TIMESTAMP)"  -f ./Dockerfile ..
 
 .PHONY: run
 run:

packages/docker-reverse-proxy/Makefile

@@ -21,7 +21,7 @@ build-debug:
 .PHONY: build-and-upload
 build-and-upload:
 	$(eval COMMIT_SHA := $(shell git rev-parse --short HEAD))
-	@docker buildx build --platform linux/amd64 --tag $(IMAGE_REGISTRY) --push --build-arg COMMIT_SHA="$(COMMIT_SHA)" -f ./Dockerfile ..
+	@docker buildx build --platform linux/$(or $(BUILD_ARCH),$(shell go env GOARCH)) --tag $(IMAGE_REGISTRY) --push --build-arg COMMIT_SHA="$(COMMIT_SHA)" -f ./Dockerfile ..
 
 .PHONY: test
 test:

packages/nomad-nodepool-apm/Makefile

@@ -11,7 +11,7 @@ BINARY := $(BIN_DIR)/$(PLUGIN_NAME)
 .PHONY: build
 build:
 	@mkdir -p $(BIN_DIR)
-	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o $(BINARY) .
+	CGO_ENABLED=0 GOOS=linux GOARCH=$(or $(BUILD_ARCH),$(shell go env GOARCH)) go build -o $(BINARY) .
 
 .PHONY: clean
 clean:

packages/orchestrator/cmd/smoketest/smoke_test.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"runtime"
 	"testing"
 	"time"
 
@@ -282,7 +283,7 @@ func findOrBuildEnvd(t *testing.T) string {
 
 	cmd := exec.CommandContext(t.Context(), "go", "build", "-o", binPath, ".") //nolint:gosec // trusted input
 	cmd.Dir = envdDir
-	cmd.Env = append(os.Environ(), "CGO_ENABLED=0", "GOOS=linux", "GOARCH=amd64")
+	cmd.Env = append(os.Environ(), "CGO_ENABLED=0", "GOOS=linux", "GOARCH="+runtime.GOARCH)
 	out, err := cmd.CombinedOutput()
 	if err != nil {
 		t.Skipf("failed to build envd: %v\n%s", err, out)