update multimodal part

[sdbds]

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[Copilot]

Pull Request Overview

This PR implements comprehensive multimodal file support for the chat application, allowing users to upload and send images, audio, video, and documents alongside text messages. The changes span frontend file handling, backend processing, and type definitions.

Key changes:

• Added file attachment functionality with drag-and-drop, paste, and file picker support
• Implemented multimodal message processing with base64 encoding for smaller files and Gemini file upload for larger files
• Updated type definitions and UI components to display uploaded files in conversations

Reviewed Changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 27 comments.

Show a summary per file

File	Description
frontend/app/stores/sessionStore.ts	Added file processing and base64 conversion to message sending
frontend/app/chat/types/conversation.ts	Extended Turn interface to include files array in inputs
frontend/app/chat/page.tsx	Updated sendMessage to accept optional files parameter
frontend/app/chat/components/details/TurnBubble.tsx	Added display logic for uploaded files in chat bubbles
frontend/app/chat/components/WelcomeScreen.tsx	Replaced custom input with ChatInput component
frontend/app/chat/components/ProjectPage.tsx	Replaced custom input with ChatInput component
frontend/app/chat/components/ChatInput.tsx	Complete rewrite with multimodal file support
core/pyproject.toml	Added httpx dependency
core/api/message_handlers.py	Enhanced message handling for multimodal payloads
core/agent_core/nodes/mcp_proxy_node.py	Added path normalization for Windows compatibility
core/agent_core/nodes/base_agent_node.py	Added multimodal content preservation and message validation
core/agent_core/framework/inbox_processor.py	Implemented comprehensive file processing with Gemini integration
core/agent_core/events/ingestors.py	Added multimodal ingestor for file attachments

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