ci: add Gitea Actions workflow for make check (closes #96)

Adds .gitea/workflows/check.yml — runs make check on pushes to main
and PRs targeting main.

Uses golangci-lint v2.10.1 (pinned) matching the repo's v2 config.
Only adds the workflow file. No other files modified.

.gitea/workflows/check.yml

@@ -0,0 +1,26 @@
+name: Check
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+
+      - name: Install golangci-lint
+        run: go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@v2.10.1
+
+      - name: Install goimports
+        run: go install golang.org/x/tools/cmd/goimports@latest
+
+      - name: Run make check
+        run: make check