Add context-aware response generator, demo session, and bug fixes

Features:
- Context-aware response generator for storyteller
  - Select multiple characters to include in context
  - Generate scene descriptions or individual responses
  - Individual responses auto-parsed and sent to each character
  - Improved prompt with explicit [CharacterName] format
  - Smart context building with character profiles and history

- Demo session auto-creation on startup
  - Pre-configured 'The Cursed Tavern' adventure
  - Two characters: Bargin (Dwarf Warrior) and Willow (Elf Ranger)
  - Quick-access buttons on home page
  - Eliminates need to recreate test data

- Session ID copy button for easy sharing

Bug Fixes:
- Fixed character chat history showing only most recent message
  - CharacterView now handles both 'storyteller_response' and 'new_message'
- Fixed all Pydantic deprecation warnings
  - Replaced .dict() with .model_dump() (9 instances)
- Fixed WebSocket manager reference in contextual responses

UI Improvements:
- Beautiful demo section with gradient styling
- Format help text for individual responses
- Improved messaging and confirmations

Documentation:
- CONTEXTUAL_RESPONSE_FEATURE.md - Complete feature documentation
- DEMO_SESSION.md - Demo session guide
- FIXES_SUMMARY.md - Bug fix summary
- PROMPT_IMPROVEMENTS.md - Prompt engineering details

.gitignore

@@ -31,6 +31,7 @@ env/
 
 # IDEs
 .vscode/
+.windsurf/
 .idea/
 *.swp
 *.swo