Add GitHub Actions for CI/CD

- Introduced a new GitHub Action .github/actions/prepare/action.yml to set up the environment for CI jobs. This action installs pnpm and Node.js and installs project dependencies.
-

Author: ryota-murakami

.github/actions/prepare/action.yml

@@ -0,0 +1,19 @@
+description: Prepares the repo for a typical CI job
+
+name: Prepare
+
+runs:
+  steps:
+    - name: Install pnpm
+      uses: pnpm/action-setup@v4
+      with:
+        version: 10
+    - name: Use Node.js
+      uses: actions/setup-node@v4
+      with:
+        node-version: '22'
+        cache: 'pnpm'
+    - name: Install dependencies
+      run: pnpm install
+      shell: bash
+  using: composite

.github/dependabot.yml

@@ -0,0 +1,8 @@
+version: 2
+updates:
+  - package-ecosystem: 'npm'
+    # Files stored in `app` directory
+    directory: '/'
+    schedule:
+      interval: 'daily'
+    target-branch: 'main'

.github/workflows/lint.yml

@@ -0,0 +1,13 @@
+name: Lint
+on:
+  pull_request: ~
+  push:
+    branches:
+      - main
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ./.github/actions/prepare
+      - run: pnpm lint

.github/workflows/test.yml

@@ -0,0 +1,17 @@
+name: Test
+on:
+  pull_request: ~
+  push:
+    branches:
+      - main
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: szenius/[email protected]
+        with:
+          timezoneLinux: 'Asia/Tokyo'
+      - uses: actions/checkout@v4
+      - uses: ./.github/actions/prepare
+      - name: Test
+        run: pnpm test