Fix Expo Router conflicting routes and update dependencies

[jeremyeder]

Summary

• Remove duplicate route app/sessions/[id].tsx that conflicted with app/sessions/[id]/index.tsx
• Update Expo SDK packages to resolve version mismatches with SDK 54
• Update dev dependencies to SDK 54-compatible versions
• Install expo-linear-gradient dependency required by react-native-gifted-charts
• Resolve all npm security vulnerabilities

Problem

The app was crashing on launch with an Expo Router error:

Found conflicting screens with the same pattern. The pattern 'sessions/:id' 
resolves to both '__root > sessions > [id]/index' and '__root > sessions > [id]'

Root Cause

Both app/sessions/[id].tsx and app/sessions/[id]/index.tsx resolve to the same route pattern /sessions/:id in Expo Router, creating a conflict.

Solution

• Deleted app/sessions/[id].tsx (standalone file)
• Kept app/sessions/[id]/index.tsx (directory-based routing with proper nested structure for review flow)
• Updated mismatched Expo packages using --legacy-peer-deps to resolve React version conflicts
• Updated dev dependencies to SDK 54 compatible versions

Test Plan

• App builds successfully for iOS simulator
• App launches without routing errors
• Metro bundler serves JavaScript correctly
• No package version warnings
• No security vulnerabilities
• Mock SSE service and real-time updates working
• Performance monitoring active

Changes

• Deleted: app/sessions/[id].tsx
• Updated: package.json - Expo SDK packages and dev dependencies
• Updated: package-lock.json - Resolved dependencies

🤖 Generated with Claude Code