feat: redesign day picker with expandable calendar, status markers & Playwright E2E testing

- Replace modal calendar with inline expandable calendar widget integrated into the day picker.
- Add status indicator dots (attended/absent/pending) to month calendar grid matching day picker.
- Disable and gray out weekend days in calendar when weekend schedule is turned off.
- Redesign extend bar with integrated handle that aligns with the palette.
- Remove start-to-end timing on Today screen's class time rail, showing only start time.
- Implement Playwright E2E and visual testing suite with multi-screen capture scripts.
- Add cascade DELETE endpoints for subjects and versioned recurring timetable entries.

package.json

@@ -9,7 +9,9 @@
     "ios": "expo start --ios",
     "web": "expo start --web",
     "lint": "expo lint",
-    "api": "node backend/server.mjs"
+    "api": "node backend/server.mjs",
+    "test:e2e": "playwright test",
+    "test:visual": "node scripts/capture-all.mjs"
   },
   "dependencies": {
     "@expo-google-fonts/manrope": "^0.4.2",
@@ -41,9 +43,11 @@
     "react-native-worklets": "0.5.1"
   },
   "devDependencies": {
+    "@playwright/test": "^1.62.1",
     "@types/react": "~19.1.0",
     "eslint": "^9.25.0",
     "eslint-config-expo": "~10.0.0",
+    "playwright": "^1.62.1",
     "typescript": "~5.9.2"
   },
   "private": true