Update outdated dependencies for security & stability"

## 🐛 Description

The project currently uses several outdated dependencies. Some of these are security-sensitive packages (e.g., `flutter_secure_storage`, `firebase_core`, `firebase_messaging`) that have newer versions with bug fixes and security improvements. Updating dependencies ensures:

- Security vulnerabilities are patched
- Compatibility with latest Flutter/Dart versions
- Stable and maintainable codebase

---

## ⚠️ Affected Dependencies

Direct dependencies that should be updated:

| Package | Current | Latest | Notes |
|---------|---------|-------|-------|
| flutter_secure_storage | 9.2.4 | 10.0.0 | Major upgrade; security fix |
| firebase_core | 4.2.1 | 4.3.0 | Minor update |
| firebase_messaging | 16.0.4 | 16.1.0 | Minor update |
| firebase_analytics | 12.0.4 | 12.1.0 | Minor update |
| google_fonts | 6.3.2 | 7.0.2 | Major upgrade; UI stability |
| app_links | 6.4.1 | 7.0.0 | Major upgrade |
| internet_connection_checker_plus | 2.7.2 | 2.9.1+2 | Minor security/compatibility update |
| livekit_client | 2.5.4 | 2.6.1 | Minor update |
| upgrader | 12.3.0 | 12.5.0 | Minor update |
| file_picker | 10.3.7 | 10.3.8 | Minor patch |
| appwrite | 20.3.2 | 20.3.3 | Minor patch |

> Note: Many transitive dependencies (like `analyzer`, `material_color_utilities`) also have newer versions.

---

## Screenshot

## 🔄 Steps to Reproduce

1. Clone the repository:
```bash
git clone https://github.com/AOSSIE-Org/Resonate.git
cd Resonate
git checkout dev
Run Flutter package manager:
```bash
flutter pub get
```

You will see the following warning:

54 packages have newer versions incompatible with dependency constraints.
Try `flutter pub outdated` for more information.

Run outdated check:
```bash
flutter pub outdated
```

Lists all outdated packages and their latest versions.

💡 Suggested Solution

Upgrade safe minor versions first:
```bash
flutter pub upgrade
```

Carefully upgrade major versions, especially security-sensitive packages:

flutter pub upgrade --major-versions

Test the app thoroughly:
```bash
flutter clean
flutter pub get
flutter run
```

✅ Expected Behavior

All dependencies should be up-to-date with latest secure versions.

App should build and run without errors.

Security vulnerabilities in older packages are patched.

📌 Additional Notes

flutter_secure_storage major version upgrade may require minor code adjustments in storage read/write calls.

js package is discontinued; evaluate if it’s needed.

This update improves security, maintainability, and compatibility with the latest Flutter/Dart SDK.

---