[BUG] Division by Zero Crash in Rating Calculations Affecting Pair Chat, Friends, and User Profiles Issue Body:

[Muneerali199]

Describe the bug

Multiple controllers perform division operations (ratingTotal / ratingCount) without checking if ratingCount is zero. This causes runtime exceptions or produces double.infinity values, leading to crashes or broken UI in critical user flows.

Affected Files & Lines

File	Line	Code
lib/controllers/pair_chat_controller.dart	83	"userRating": authController.ratingTotal / authController.ratingCount
lib/controllers/friends_controller.dart	69	authStateController.ratingTotal / authStateController.ratingCount
lib/controllers/user_profile_controller.dart	153	userData['ratingTotal'] / userData['ratingCount']
lib/controllers/explore_story_controller.dart	202, 221	userData['ratingTotal'] / userData['ratingCount']

Root Cause

In lib/controllers/auth_state_controller.dart (lines 50-51), the rating fields are declared as late:

late double ratingTotal;
late int ratingCount;
For new users or uninitialized state, ratingCount can be 0, causing division by zero.
Impact
- Pair Chat: Matching fails or shows broken rating UI
- Friends Screen: Friend request cards crash or display ∞ rating
- User Profile: Profile screen crashes when viewing new users
- Story Explore: Story cards show invalid ratings
Steps to Reproduce
1. Create a new user account with no ratings
2. Navigate to Pair Chat screen
3. Observe crash or broken UI
4. Navigate to Friends screen
5. Observe crash or double.infinity displayed
Expected Behavior
- New users should display a default rating (e.g., 5.0 or "No ratings yet")
- Division should be guarded with zero-checks
- UI should gracefully handle uninitialized rating state
Suggested Fix
// In auth_state_controller.dart - initialize with safe defaults
double ratingTotal = 5.0;
int ratingCount = 1;
// At all division sites, add guards:
double userRating = ratingCount > 0 ? ratingTotal / ratingCount : 5.0;
// Or use null-aware pattern:
double? get averageRating => ratingCount > 0 ? ratingTotal / ratingCount : null;
Additional Context
This is a structural hardening issue that affects core user flows. The fix requires:
1. Safe initialization of rating fields
2. Zero-check guards at all 6 division sites
3. UI fallbacks for null/zero rating states

[github-actions]

👋 Hello @Muneerali199!
Thank you for opening this issue. Our team will review it soon. 🚀

• If you can, please provide more details like steps to reproduce, expected vs. actual behavior, and screenshots (if applicable). 📌

We appreciate your contribution! 💡

[Muneerali199]

please assign me this issue when you are free