Add image and GIF vision support

- Add ImageAttachment dataclass for image metadata
- Update Message to support list of image attachments
- Update all providers (OpenAI, Anthropic, Gemini, OpenRouter) for vision
- Extract images from Discord attachments and embeds in ai_chat.py
- Supports PNG, JPEG, GIF, and WebP formats

src/daemon_boyfriend/services/__init__.py

@@ -2,12 +2,13 @@
 
 from .ai_service import AIService
 from .conversation import ConversationManager
-from .providers import AIResponse, Message
+from .providers import AIResponse, ImageAttachment, Message
 from .searxng import SearXNGService
 
 __all__ = [
     "AIService",
     "AIResponse",
+    "ImageAttachment",
     "Message",
     "ConversationManager",
     "SearXNGService",