## 1. Project setup

- [ ] 1.1 Scaffold the `Next.js` app with TypeScript, linting, and baseline project configuration.
- [ ] 1.2 Add runtime dependencies for Prisma, SQLite, validation, charts, and `OpenAI` integration.
- [ ] 1.3 Add development dependencies and scripts for testing, Prisma generation, and local development.
- [ ] 1.4 Add base environment and ignore-file setup for local database and API key configuration.

## 2. Persistence and shared services

- [ ] 2.1 Define Prisma models for `Expense`, `Paycheck`, and `MonthlyInsight` and create the initial SQLite migration.
- [ ] 2.2 Implement shared validation schemas for expenses, paychecks, and month query parameters.
- [ ] 2.3 Implement shared money and local-date utilities for month boundary calculations.

## 3. Expense and paycheck workflows

- [ ] 3.1 Implement expense API routes for create, list, and delete operations.
- [ ] 3.2 Implement paycheck API routes for create, list, and delete operations.
- [ ] 3.3 Build the `Add Expense` view with form submission, validation feedback, and expense listing.
- [ ] 3.4 Build the `Income/Paychecks` view with form submission, validation feedback, and paycheck listing.

## 4. Dashboard and insights

- [ ] 4.1 Implement monthly dashboard aggregation services for totals, category breakdowns, and derived comparisons.
- [ ] 4.2 Implement the dashboard API route and render dashboard sections for month-to-date metrics and comparisons.
- [ ] 4.3 Implement the `OpenAI` insight service with structured monthly snapshot input and sparse-month fallback logic.
- [ ] 4.4 Implement insight generation and display in the dashboard, including persisted monthly insight records.

## 5. Verification

- [ ] 5.1 Add automated tests for validation, persistence, dashboard aggregates, and insight fallback behavior.
- [ ] 5.2 Verify the primary user flows in the browser, including expense entry, paycheck entry, dashboard updates, and insight generation.