Expand unit test coverage and add PR preview deployments

.github/workflows/preview.yml

@@ -0,0 +1,71 @@
+name: PR Preview
+
+on:
+  pull_request:
+    branches: [main]
+    types: [opened, synchronize, reopened]
+
+permissions:
+  contents: read
+  pull-requests: write
+  deployments: write
+
+concurrency:
+  group: preview-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
+jobs:
+  preview:
+    name: Deploy PR Preview
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+      - run: npm ci
+      - name: Build
+        env:
+          VITE_GOOGLE_CLIENT_ID: ${{ secrets.VITE_GOOGLE_CLIENT_ID }}
+          VITE_GITHUB_CLIENT_ID: ${{ secrets.VITE_GITHUB_CLIENT_ID }}
+        run: npm run build
+      - name: Publish preview to Cloudflare Pages
+        id: deploy
+        uses: cloudflare/wrangler-action@v3
+        with:
+          apiToken: ${{ secrets.CLOUDFLARE_API_TOKEN }}
+          accountId: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}
+          command: pages deploy dist --project-name=sinter --branch=${{ github.head_ref }}
+      - name: Comment preview URL on the PR
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const marker = '<!-- pr-preview-comment -->';
+            const aliasUrl = `${{ steps.deploy.outputs.pages-deployment-alias-url }}`;
+            const deploymentUrl = `${{ steps.deploy.outputs.deployment-url }}`;
+            const url = aliasUrl || deploymentUrl;
+            const body = `${marker}\n🚀 Preview deployed: ${url}\n\n(updates on every push to this PR)`;
+
+            const { data: comments } = await github.rest.issues.listComments({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: context.issue.number,
+            });
+            const existing = comments.find((c) => c.body.includes(marker));
+
+            if (existing) {
+              await github.rest.issues.updateComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                comment_id: existing.id,
+                body,
+              });
+            } else {
+              await github.rest.issues.createComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                issue_number: context.issue.number,
+                body,
+              });
+            }

.gitignore

@@ -6,4 +6,5 @@ data/
 .env
 test-results/
 playwright-report/
+coverage/
 .env.swp