Add golangci-lint locally and in CI

.github/workflows/ci.yml

@@ -0,0 +1,29 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  lint:
+    name: Lint
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v6
+
+      - name: Set up Go
+        uses: actions/setup-go@v6
+        with:
+          go-version-file: go.mod
+
+      - name: Run golangci-lint
+        uses: golangci/golangci-lint-action@v9
+        with:
+          version-file: .tool-versions

.tool-versions

@@ -0,0 +1 @@
+golangci-lint 2.8.0

Makefile

@@ -1,7 +1,7 @@
 BINARY_NAME=lstk
 BUILD_DIR=bin
 
-.PHONY: build clean test test-integration mock-generate
+.PHONY: build clean test test-integration lint mock-generate
 
 build:
 	go build -o $(BUILD_DIR)/$(BINARY_NAME) .
@@ -17,3 +17,9 @@ test-integration: build
 
 mock-generate:
 	go generate ./...
+
+lint:
+	@EXPECTED=$$(awk '/^golangci-lint/ {print $$2}' .tool-versions); \
+	INSTALLED=$$(golangci-lint version --short 2>/dev/null | sed 's/^v//'); \
+	[ "$$INSTALLED" = "$$EXPECTED" ] || { echo "golangci-lint $$EXPECTED required (found: $$INSTALLED)"; exit 1; }
+	golangci-lint run