Feature Request: Support Android's AppFunctions

See https://android-developers.googleblog.com/2026/02/the-intelligent-os-making-ai-agents.html.

For future Android version, AppFunctions will be the critical module leveraged by AI Assistant and apps to communicate on Android platform. It's likely a MCP server. For goose-mobile's Android version, what about supporting AppFunctions like Gemini does?

The issue references a future Android feature called AppFunctions, possibly an MCP server, and suggests supporting it like Gemini does. Start by reading the linked blog post to understand AppFunctions. Examine the goose-mobile codebase for existing Android integration points and AI/agent communication modules. Determine what an MCP server implementation would entail and how it would interface with the mobile platform.

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