Resolve merge conflicts with origin/main

Conflicts in script.js and sw.js arose because this branch contains an
earlier rift-mode implementation that diverged from the evolved version
now on main. Resolved all conflicts in favour of main's more complete
rift-mode code (TEST_MODE infrastructure, debounce timers, modal button
refs, extension hooks, solvability-check throttling, cache version bump).

https://claude.ai/code/session_01DXVYAJC4gFReBdx8eJqpsi

Author: claude

.github/workflows/spit-the-diff.yml

@@ -0,0 +1,20 @@
+name: spit-the-diff
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened, labeled]
+
+jobs:
+  spit-the-diff:
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Generate PR summary
+        uses: ssfinney/spit-the-diff@1.1.2
+        with:
+          format: haiku
+          openai_api_key: ${{ secrets.OPENAI_API_KEY }}

.github/workflows/ui-tests.yml

@@ -0,0 +1,37 @@
+name: ui-tests
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  playwright:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Install Playwright browsers
+        run: npx playwright install --with-deps chromium
+
+      - name: Run UI tests
+        run: npm run test:ui
+
+      - name: Upload Playwright artifacts on failure
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: playwright-artifacts
+          path: |
+            playwright-report/
+            test-results/
+          if-no-files-found: ignore

.gitignore

@@ -1,2 +1,3 @@
 node_modules/
-package-lock.json
+playwright-report/
+test-results/