ci: add main ci workflow

.github/workflows/main.yaml

@@ -0,0 +1,40 @@
+name: Main
+
+on:
+  push:
+    branches: [main]
+    tags: ["v*"]
+  pull_request:
+    branches: [main]
+
+permissions:
+  contents: read
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: 'go.mod'
+      - name: Format
+        run: go fmt ./... && git diff --exit-code
+      - name: Vet
+        run: go vet ./...
+      - name: Lint
+        uses: golangci/golangci-lint-action@v6
+        with:
+          version: v1.58
+      - name: Mod tidy
+        run: go mod tidy && git diff --exit-code
+      - name: Mod download
+        run: go mod download
+      - name: Mod verify
+        run: go mod verify
+      - name: Test
+        run: go test -v -race -shuffle=on -coverprofile=coverage.txt ./...
+      - name: Build
+        run: go build -o /dev/null ./cmd/zettelkasten-exporter/main.go