Add getLeaveStatus utility and update project status

- Introduce `getLeaveStatus` function in `packages/core/src/status-utils.ts` to determine leave-by status based on
  journey data
- Mark Phase 1 mobile app tasks as complete in `CHECKLIST.md`
- Add mobile workspace configurations and npm scripts

apps/mobile/app.json

@@ -0,0 +1,36 @@
+{
+  "expo": {
+    "name": "Time To Leave",
+    "slug": "timetoleave",
+    "version": "1.0.0",
+    "orientation": "portrait",
+    "icon": "./assets/icon.png",
+    "userInterfaceStyle": "light",
+    "newArchEnabled": true,
+    "splash": {
+      "image": "./assets/splash-icon.png",
+      "resizeMode": "contain",
+      "backgroundColor": "#007AFF"
+    },
+    "ios": {
+      "supportsTablet": true,
+      "bundleIdentifier": "at.timetoleave.mobile"
+    },
+    "android": {
+      "adaptiveIcon": {
+        "foregroundImage": "./assets/adaptive-icon.png",
+        "backgroundColor": "#007AFF"
+      },
+      "edgeToEdgeEnabled": true,
+      "predictiveBackGestureEnabled": false,
+      "package": "at.timetoleave.mobile"
+    },
+    "web": {
+      "favicon": "./assets/favicon.png"
+    },
+    "plugins": [
+      "expo-location",
+      "expo-notifications"
+    ]
+  }
+}