I need a complete desktop application that will centralise and automate my daily business-management tasks. The program should run natively on Windows (macOS compatibility would be a welcome bonus) and handle core functions such as client records, invoicing, inventory tracking, simple analytics and user-level access control—all within an intuitive, modern interface. My priority is stability and long-term maintainability, so I’d like the codebase written in a widely supported language (C#, Java or Python with a robust GUI framework are all acceptable). A lightweight local database is fine for now, but the architecture should leave room for us to migrate to a cloud-hosted SQL solution later. Please include: • An installer or portable build that works out of the box • Source code with clear inline comments and a short setup/read-me file • Basic test data so I can see the key workflows in action If we move forward, I’ll share a detailed feature list and brand assets. For the proposal, give me a brief outline of the tech stack you prefer, any similar desktop apps you have built, and an estimated timeline for first runnable demo and final delivery.