feat: optimize GitHub Actions E2E test performance (#8)

* feat: optimize GitHub Actions E2E test performance

- Add Playwright browser caching to avoid re-downloading browsers
- Cache build artifacts to skip rebuilds when code hasn't changed
- Enable parallel test execution (workers: 2) for faster runs
- Reduce test matrix to Chromium only (3x speedup)
- Keep Firefox/WebKit commented for easy re-enabling

Expected performance improvement: 50-70% reduction in CI time

🤖 Generated with [Claude Code](https://claude.ai/code)

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

* chore: remove unnecessary NPM_TOKEN from GitHub Actions workflows

Remove NPM_TOKEN environment variable from all workflow files as it's no longer needed

🤖 Generated with [Claude Code](https://claude.ai/code)

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

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: fyuuki0jp

.github/workflows/e2e-tests.yml

@@ -6,9 +6,6 @@ on:
   pull_request:
     branches: [main]
 
-env:
-  NPM_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
 jobs:
   playwright:
     name: Run Playwright Tests
@@ -34,10 +31,40 @@ jobs:
       - name: Refresh package links
         run: yarn install --force
 
+      - name: Get Playwright version
+        id: playwright-version
+        run: echo "version=$(yarn list --pattern @playwright/test --depth=0 --json --non-interactive --no-progress | jq -r '.data.trees[0].name' | sed 's/@playwright\/test@//')" >> $GITHUB_OUTPUT
+
+      - name: Cache Playwright browsers
+        uses: actions/cache@v4
+        id: playwright-cache
+        with:
+          path: ~/.cache/ms-playwright
+          key: ${{ runner.os }}-playwright-${{ steps.playwright-version.outputs.version }}
+          restore-keys: |
+            ${{ runner.os }}-playwright-
+
       - name: Install Playwright browsers
+        if: steps.playwright-cache.outputs.cache-hit != 'true'
         run: npx playwright install --with-deps
 
+      - name: Install Playwright system dependencies
+        if: steps.playwright-cache.outputs.cache-hit == 'true'
+        run: npx playwright install-deps
+
+      - name: Cache build artifacts
+        uses: actions/cache@v4
+        id: build-cache
+        with:
+          path: |
+            backend/dist
+            frontend/dist
+          key: ${{ runner.os }}-build-${{ hashFiles('**/yarn.lock', '**/package.json', '**/*.ts', '**/*.tsx', '!**/*.spec.ts', '!**/*.test.ts') }}
+          restore-keys: |
+            ${{ runner.os }}-build-
+
       - name: Build applications
+        if: steps.build-cache.outputs.cache-hit != 'true'
         run: yarn build
 
       - name: Run Playwright tests

.github/workflows/lint-typecheck.yml

@@ -6,9 +6,6 @@ on:
   pull_request:
     branches: [main]
 
-env:
-  NPM_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
 jobs:
   lint:
     name: Run Linting and Type Checking

.github/workflows/unit-tests.yml

@@ -6,9 +6,6 @@ on:
   pull_request:
     branches: [main]
 
-env:
-  NPM_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
 jobs:
   test:
     name: Run Unit Tests

playwright.config.ts

@@ -7,13 +7,13 @@ import { defineConfig, devices } from '@playwright/test';
 export default defineConfig({
   testDir: './e2e',
   /* Run tests in files in parallel */
-  fullyParallel: false,
+  fullyParallel: true,
   /* Fail the build on CI if you accidentally left test.only in the source code. */
   forbidOnly: !!process.env.CI,
   /* Retry on CI only */
   retries: process.env.CI ? 2 : 0,
   /* Opt out of parallel tests on CI. */
-  workers: process.env.CI ? 1 : undefined,
+  workers: process.env.CI ? 2 : undefined,
   /* Reporter to use. See https://playwright.dev/docs/test-reporters */
   reporter: process.env.CI ? 'html' : 'line',
   /* Shared settings for all the projects below. See https://playwright.dev/docs/api/class-testoptions. */
@@ -32,15 +32,17 @@ export default defineConfig({
       use: { ...devices['Desktop Chrome'] },
     },
 
-    {
-      name: 'firefox',
-      use: { ...devices['Desktop Firefox'] },
-    },
+    // Firefox and webkit are commented out to speed up CI
+    // Uncomment if cross-browser testing is required
+    // {
+    //   name: 'firefox',
+    //   use: { ...devices['Desktop Firefox'] },
+    // },
 
-    {
-      name: 'webkit',
-      use: { ...devices['Desktop Safari'] },
-    },
+    // {
+    //   name: 'webkit',
+    //   use: { ...devices['Desktop Safari'] },
+    // },
 
     /* Test against mobile viewports. */
     // {