Cache node_modules from build job, restore in e2e

Build job saves node_modules to actions/cache, e2e jobs restore it
read-only. Eliminates ~2min npm install per matrix entry.

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

Author: Platane

.github/workflows/ci.yml

@@ -24,6 +24,12 @@ jobs:
           node-version: '22'
           cache: 'npm'
 
+      - name: Cache node_modules for future jobs
+        uses: actions/cache@v4
+        with:
+          path: node_modules
+          key: node-modules-${{ hashFiles('package-lock.json') }}
+
       - name: Install dependencies
         run: npm ci
 
@@ -85,7 +91,7 @@ jobs:
       matrix:
         GRAFANA_IMAGE:
           - name: grafana-oss
-            version: "12.4.0"
+            version: '12.4.0'
         QUICKWIT_VERSION: [edge]
     steps:
       - uses: actions/checkout@v6
@@ -103,10 +109,15 @@ jobs:
         uses: actions/setup-node@v6
         with:
           node-version: '22'
-          cache: 'npm'
 
-      - name: Install e2e dependencies
-        run: npm install --no-save @grafana/plugin-e2e @playwright/test && npx playwright install --with-deps chromium
+      - name: Restore node_modules
+        uses: actions/cache/restore@v4
+        with:
+          path: node_modules
+          key: node-modules-${{ hashFiles('package-lock.json') }}
+
+      - name: Install Playwright
+        run: npx playwright install --with-deps chromium
 
       - name: Start Grafana (${{ matrix.GRAFANA_IMAGE.name }}:${{ matrix.GRAFANA_IMAGE.version }}) + Quickwit (${{ matrix.QUICKWIT_VERSION }})
         run: docker compose up -d --build