Add project-aware Coproducer and MCP server #1941

Summary

This PR adds Coproducer, a project-aware AI assistant for Shotcut, and exposes its tools through a Streamable HTTP MCP endpoint. Coproducer and external MCP clients use the same endpoint.

Coproducer

• Adds a QML-based Coproducer dock, opened with Ctrl+Shift+7.


• Adds Chat and Search User Guide entries to Help.


• Adds two interchangeable AI provider modes:
  
  
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    OpenAI-compatible API: configure the API key, model, and base URL. HTTPS is required except for localhost endpoints.
  
  
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    Local model: select a GGUF model; Shotcut starts and manages llama-server.
  
  
  
  


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  AI Chat sends model-requested tools through MCP for project inspection, timeline summaries, and forum search.


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  Search User Guide calls the forum-search MCP tool directly, without invoking an AI model.


• Streams Markdown responses, supports citations, and includes cancellation and new-chat controls.

MCP

• Implements a stateless Streamable HTTP endpoint at /mcp, with dynamic localhost ports and MCP initialization, tool discovery, and tool calls.


• Adds Help → Copy MCP Endpoint so users can provide the current Shotcut instance’s URL to external MCP clients.


• Registers three tools: shotcut_project_inspect, shotcut_timeline_summary, and shotcut_forum_search.


• Project inspection returns read-only clip, playlist, timeline, and UI context. Timeline summaries can omit per-track details to reduce payload size.


• Restricts connections to loopback and validates Host and Origin headers.


• Moves MCP-only forum search and project inspection into the mcp/ module.

Testing

• MCP tests cover initialization, tool listing and calls, per-instance isolation, HTTP Origin and GET handling, and timeline summary track inclusion.


• MCP Inspector was used to verify connection, tool discovery, and tool calls.