Full-Stack Developer Needed for Custom Internal Fleet Maintenance & Recommendation Dashboard

I am looking for a full-stack developer to build a lightweight, single-page web application to be used internally by service advisors at our automotive workshop desktop counters. How the software should work: The Advisor Input: When a vehicle arrives, the advisor will type three things into a clean dashboard: the vehicle model (from a dropdown), the current odometer reading, and the last odometer reading when a specific major job (like an oil change) was previously done. The Calculation Logic: The software needs to subtract the "Last Done" kilometers from the "Current" kilometers, and check the result against a master maintenance frequency table stored in the database. The Simple Output: If a job is due or overdue based on that math, it should instantly pop up on a clean checklist on the advisor's screen. Next to each due job, it must display a short, 2-line "Technical Explanation text" pulled from the database to help the advisor explain the job to the customer. Admin Panel: I need a private settings page where I can manually add new vehicle types, change the kilometer intervals, and edit the explanation text myself via a simple form, without editing any code. Important Data, Workflow & Budget Notes: The Workflow Environment: Our workshop currently runs on SAP DBM for standard billing and job card creation. Because SAP DBM is locked down, this new software will run completely standalone in a browser tab right next to it. We are highly open to your creative ideas on how to design this user interface to make it as simple, fast, and frictionless as possible for an advisor who is multitasking between SAP and this tool. (We can discuss this further). Data Security: To protect our workshop's specific data, the project will be developed entirely using fake/placeholder text and numbers (e.g., "Vehicle X", "Job Alpha", "Interval 5000"). Once the software is fully completed and deployed, we will input our actual service data ourselves via the Admin Panel. Budget: We are looking to build a cost-effective, Please quote keeping a lean budget and fast delivery in mind.