feat: build linux/darwin amd64/arm64 binaries in parallel

Each target gets its own step depending on test, so all four build
concurrently. release step waits for all builds before uploading.

💘 Generated with Crush

Assisted-by: Claude Sonnet 4.6 via Crush <crush@charm.land>

.woodpecker/release.yaml

@@ -7,12 +7,28 @@ steps:
     commands:
       - go test ./...
 
-  - name: build
+  - name: build-linux-amd64
     image: golang:latest
     commands:
-      - VERSION=${CI_COMMIT_TAG}
-      - BINARY=node-lookup-linux-amd64
-      - go build -ldflags="-s -w -X main.version=${VERSION}" -o ${BINARY} ./...
+      - GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X main.version=${CI_COMMIT_TAG}" -o node-lookup-linux-amd64 ./...
+    depends_on: [test]
+
+  - name: build-linux-arm64
+    image: golang:latest
+    commands:
+      - GOOS=linux GOARCH=arm64 go build -ldflags="-s -w -X main.version=${CI_COMMIT_TAG}" -o node-lookup-linux-arm64 ./...
+    depends_on: [test]
+
+  - name: build-darwin-amd64
+    image: golang:latest
+    commands:
+      - GOOS=darwin GOARCH=amd64 go build -ldflags="-s -w -X main.version=${CI_COMMIT_TAG}" -o node-lookup-darwin-amd64 ./...
+    depends_on: [test]
+
+  - name: build-darwin-arm64
+    image: golang:latest
+    commands:
+      - GOOS=darwin GOARCH=arm64 go build -ldflags="-s -w -X main.version=${CI_COMMIT_TAG}" -o node-lookup-darwin-arm64 ./...
     depends_on: [test]
 
   - name: release
@@ -31,8 +47,13 @@ steps:
           NOTES=$(git log --merges --pretty=format:"- %s")
         fi
         tea releases edit "${CI_COMMIT_TAG}" --note "${NOTES}" --login gitea --repo "${CI_REPO}"
-        tea releases assets create "${CI_COMMIT_TAG}" node-lookup-linux-amd64 --login gitea --repo "${CI_REPO}"
+        tea releases assets create "${CI_COMMIT_TAG}" \
+          node-lookup-linux-amd64 \
+          node-lookup-linux-arm64 \
+          node-lookup-darwin-amd64 \
+          node-lookup-darwin-arm64 \
+          --login gitea --repo "${CI_REPO}"
     backend_options:
       kubernetes:
         serviceAccountName: default
-    depends_on: [build]
+    depends_on: [build-linux-amd64, build-linux-arm64, build-darwin-amd64, build-darwin-arm64]