ci: reduce CI minute consumption

.github/workflows/nightly-tests.yml

@@ -0,0 +1,55 @@
+name: Nightly Full Test Suite
+
+on:
+  schedule:
+    # Run at 6:00 AM UTC (1:00 AM EST) daily
+    - cron: '0 6 * * *'
+  workflow_dispatch:
+
+env:
+  CI: true
+
+jobs:
+  full-unit-tests:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout Code
+        uses: actions/checkout@v4
+
+      - name: Set Up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+
+      - name: Cache node_modules
+        id: cache-node-modules
+        uses: actions/cache@v4
+        with:
+          path: node_modules
+          key: node-modules-${{ runner.os }}-node20-${{ hashFiles('package-lock.json') }}
+
+      - name: Validate cached node_modules
+        id: validate-cache
+        if: steps.cache-node-modules.outputs.cache-hit == 'true'
+        run: |
+          if npm ls --depth=0 >/dev/null 2>&1; then
+            echo "valid=true" >> $GITHUB_OUTPUT
+          else
+            echo "valid=false" >> $GITHUB_OUTPUT
+            rm -rf node_modules
+          fi
+
+      - name: Install Dependencies
+        if: steps.cache-node-modules.outputs.cache-hit != 'true' || steps.validate-cache.outputs.valid == 'false'
+        run: npm ci
+
+      - name: Run full unit test suite
+        run: npm run test:unit:coverage
+
+      - name: Upload Coverage
+        uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: nightly-unit-test-coverage
+          path: coverage/
+          retention-days: 7