Can I vibecode Tallymeter?

You are an expert full-stack developer and UI/UX designer. Your task is to build a high-quality, professional freelance time tracker and invoicing application inspired by Tallymeter. The application must run locally on my machine, ensuring complete privacy (no telemetry, no accounts).

## Tech Stack
- Backend: Node.js, Express, better-sqlite3 (single process)
- Frontend: HTML/CSS/JS (vanilla or lightweight frameworks like Alpine.js/Tailwind CSS for styling), server-rendered pages or a lightweight SPA
- Output: PDF generation via Puppeteer
- Port: Localhost 4820

## Data Models
1. **Clients**: id, name, email, address, created_at
2. **Projects**: id, client_id, name, hourly_rate, currency, created_at
3. **Entries**: id, project_id, description, started_at (ISO-8601 UTC), ended_at (ISO-8601 UTC), invoice_id (nullable)
4. **Invoices**: id, client_id, project_id, invoice_number (e.g., INV-2026-001), total_amount, issued_at, status (draft, paid)

## UI & UX Requirements
- **Aesthetics**: The application should have a stunning, modern design. Use a sleek dark mode by default, with vibrant accent colors (e.g., electric blue or neon green for active states). Incorporate glassmorphism for modal overlays, smooth transitions on hover, and modern typography (e.g., Inter or Roboto). It must not look like a basic MVP; it should feel premium and responsive.
- **Index Page (Dashboard)**: A massive, satisfying "Start/Stop" button at the center. When a timer starts, display a real-time pulsing counter. Starting a new timer must automatically stop any currently running timer. Below the timer, list today's tracked entries.
- **Entry Management**: Allow in-place editing of finished entries (description, project). Provide an intuitive UI to manually add past entries (e.g., "Forgot to track a 30m call"). If an entry is linked to an invoice (invoice_id is not null), freeze it and disable editing.
- **Unbilled Page (/unbilled)**: Display finished entries lacking an invoice_id. Group them by project. Show hours formatted elegantly (e.g., "3h 25m") alongside the calculated total based on the project's rate.
- **Invoice Generation**: Select unbilled entries for a project and generate an invoice. Invoices must have sequential, non-reusable IDs (INV-YYYY-XXX). Render invoices as beautiful, professional PDFs using Puppeteer. Save them locally to `./invoices/INV-YYYY-XXX.pdf` and link the entries to the new invoice_id. Pull bank details, VAT rate, and freelancer info from a local `config.json`.

## Deliverables
- A complete, working codebase adhering to the above specs.
- A `README.md` explaining the `config.json` structure, where generated PDFs are stored, setup instructions (`npm start`), and a stern warning: the SQLite file is the ONLY copy of their billing history, so they must back it up.
- Exclude multi-user accounts, payment processing, or mobile apps from the scope. Focus heavily on a flawless single-user local experience with impeccable visual polish.