ci: add GitHub Actions test workflow

Runs unit tests on push to main and PRs, with caching, concurrency
control, minimal permissions, and pinned action versions.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: Nick Ficano

.github/workflows/test.yml

@@ -0,0 +1,90 @@
+# CI for typescript-sdk (ARCP)
+#
+# Action pinning policy:
+#   - First-party actions (actions/*) use major version tags (e.g. @v4).
+#   - Third-party actions are pinned to a full commit SHA with a version comment.
+#
+# package.json engines.node: ">=22"
+# Matrix covers floor (22), active LTS (22), and latest (24).
+
+name: test
+
+on:
+  push:
+    branches: [main]
+    paths-ignore:
+      - "**.md"
+      - "docs/**"
+      - "LICENSE"
+      - ".gitignore"
+      - ".editorconfig"
+  pull_request:
+    branches: [main]
+    paths-ignore:
+      - "**.md"
+      - "docs/**"
+      - "LICENSE"
+      - ".gitignore"
+      - ".editorconfig"
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    name: test (node ${{ matrix.node }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        node: ["22", "24"]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 1
+
+      - name: Setup pnpm
+        # pnpm/action-setup v4.0.0
+        uses: pnpm/action-setup@a7487c7e89a18df4991f7f222e4898a00d66ddda # v4.0.0
+        with:
+          version: 9.15.0
+          run_install: false
+
+      - name: Setup Node.js ${{ matrix.node }}
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node }}
+          cache: "pnpm"
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: Lint
+        run: pnpm run lint
+
+      - name: Typecheck
+        run: pnpm run typecheck
+
+      - name: Build
+        run: pnpm run build
+
+      - name: Test
+        run: pnpm test
+
+      - name: Upload test artifacts on failure
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: test-artifacts-node-${{ matrix.node }}
+          path: |
+            coverage/
+            test-results/
+            *.log
+          if-no-files-found: ignore
+          retention-days: 7