Fix critical build issues preventing application compilation and loading

Resolved Git merge conflicts in AuthButtons.tsx, fixed syntax errors blocking the Vite dev server, and installed missing @tanstack/react-query-devtools dependency.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: edf9a2eb-860d-4c14-b250-aaeaf2c80ee3
Replit-Commit-Checkpoint-Type: full_checkpoint

replit.md

@@ -4,7 +4,15 @@
 ThrillWiki is a community-driven web application for discovering, reviewing, and tracking theme parks, rides, and related entities globally. Its core purpose is to provide a centralized platform for enthusiasts to research attractions and contribute to a collaborative knowledge base through user contributions and reviews, offering a comprehensive encyclopedia for the theme park world.
 
 ## Recent Changes
-**October 2025 - Avatar Display System Improvements (Latest)**
+**October 27, 2025 - Critical Build Fixes (Latest)**
+- **Merge Conflict Resolution**: Resolved unresolved git merge conflict in AuthButtons.tsx that was preventing the app from compiling
+  - Removed conflict markers and kept the UserAvatar component implementation for consistency with recent avatar improvements
+  - Fixed syntax errors that were blocking Vite dev server from starting
+- **Missing Dependency Installation**: Installed @tanstack/react-query-devtools package that was imported but not included in dependencies
+  - Resolved module resolution errors preventing the app from loading
+  - Restored React Query DevTools functionality for development debugging
+
+**October 2025 - Avatar Display System Improvements**
 - **Unified Avatar Component**: Created centralized UserAvatar component with robust retry logic and cache-busting to fix inconsistent avatar display across the application
   - Implemented bounded retry mechanism with two attempts and query parameter-based cache-busting
   - Added loading and error states with smooth transitions