ci: add test workflow

Runs go test -race -v ./... on push and PRs to main.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.forgejo/workflows/test.yml

@@ -0,0 +1,22 @@
+name: Tests
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: https://github.com/actions/checkout@v4
+
+      - name: Set up Go
+        uses: https://github.com/actions/setup-go@v5
+        with:
+          go-version: '1.24'
+
+      - name: Test
+        run: go test -race -v ./...