feat(meetings): implement architecture and design for meetings feature

[JGaldo-beep]

• Add architecture and design documentation for the meetings feature.
• Define data model for meetings, including JSON schema and Rust types.
• Implement RESTful routes for meetings CRUD operations in the engine.
• Create new Tauri commands for managing meetings in the app.
• Develop React components for the meetings page, including navigation and UI elements.
• Establish event handling for meeting status changes and updates.
• Outline implementation plan with incremental phases for development and testing.

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• I read the diff myself before opening this PR (AI-assisted is fine, AI-unreviewed is not)
• I have no other open PRs on this repo
• pnpm typecheck passes
• cargo check --workspace passes (if Rust touched)
• cargo test --workspace passes (if Rust touched)
• No external frameworks/methodology imported into knowledge-base/ or docs/