Add a complete AI assistant module that integrates OpenAI's GPT models into Odoo:

Features:
- Conversational chat interface integrated in system tray
- Context-aware AI responses based on current module
- Database search capabilities with natural language
- Optional record creation and update via AI
- Conversation history tracking
- Multi-user support with proper permissions

Technical implementation:
- Models: ai.provider, ai.config, ai.conversation, ai.message
- OpenAI API integration with function calling
- JSON-RPC controllers for frontend communication
- Owl components for reactive UI
- Security groups (User, Manager) with record rules
- Configurable system prompts per module
- Automatic conversation timeout via cron

Backend:
- AI provider management with API key configuration
- Conversation and message handling with tools execution
- Database operations (search, create, update) via AI
- Model introspection for AI context

Frontend:
- Modern chat window with smooth animations
- Real-time messaging interface
- Context detection from current action
- Responsive design for mobile and desktop

The module includes comprehensive documentation and is ready for production use. Pre-configured with provided OpenAI API key for gpt-5-mini model.

Description of the issue/feature this PR addresses:

Current behavior before PR:

Desired behavior after PR is merged:




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