feat: improve docs

Author: khangtrannn

README.md

@@ -41,7 +41,7 @@ These are intentional extras beyond the assessment requirements:
 
 - **Live demo** at custom domains (Cloudflare Pages + Railway).
 - **CI → gated deploy pipeline** - production deploy only fires after CI succeeds on `main` via a `workflow_run` trigger.
-- **A4 print-to-PDF** without a PDF library - pure CSS `@media print` swap. See [`frontend/src/features/invoices/detail/InvoicePrintDocument.tsx`](./frontend/src/features/invoices/detail/InvoicePrintDocument.tsx).
+- **A4 print-to-PDF** without a PDF library - pure CSS `@media print` swap. See [`frontend/src/features/invoices/detail/components/InvoicePrintDocument.tsx`](./frontend/src/features/invoices/detail/components/InvoicePrintDocument.tsx).
 - **Runtime Zod validation** at the frontend API boundary - every response is parsed; schema drift fails loudly. See [`frontend/src/api/invoices.schema.ts`](./frontend/src/api/invoices.schema.ts).
 - **Summary dashboard endpoint** - `GET /invoices/summary` returns aggregated totals/counts respecting the same filters as `GET /invoices`. Powers the invoice list tiles.
 - **`Decimal.js` precision arithmetic** - money math never touches IEEE-754 floats. See [`backend/src/invoices/domain/invoice-calculation.ts`](./backend/src/invoices/domain/invoice-calculation.ts).
@@ -146,6 +146,7 @@ Docker Compose reads the root `.env` for container wiring and `backend/.env` for
 | `JWT_SECRET`        | Secret for signing JWT tokens (min 32 chars) | -             |
 | `JWT_EXPIRES_IN`    | Token expiry in seconds                      | `3600`        |
 | `CORS_ORIGIN`       | Comma-separated allowlist of permitted origins | `http://localhost:3000,https://simpleinvoice.khangtran.dev` |
+| `VITE_API_URL`      | Base URL for frontend API calls (backend API) | `http://localhost:4000` |
 
 ---
 

backend/.env.example

@@ -2,7 +2,7 @@
 NODE_ENV=development
 PORT=4000
 # Comma-separated allowlist of origins permitted by CORS.
-CORS_ORIGIN=http://localhost:3000,https://simpleinvoice.khangtran.dev
+CORS_ORIGIN=http://localhost:3000,http://localhost:5173,https://simpleinvoice.khangtran.dev
 
 # Database - host is 'localhost' for local dev; overridden to 'postgres' in Docker
 POSTGRES_HOST=localhost

backend/README.md

@@ -145,19 +145,6 @@ Database constraints protect invariants at the storage boundary even if a future
 
 ---
 
-## Reviewer Quick Start
-
-See the [root README](../README.md) for full setup instructions (Docker or local). This section highlights backend-specific endpoints and credentials.
-
-### Default Credentials
-
-Seeded automatically by `npm run seed`:
-
-```
-Email:    reviewer@simpleinvoice.local
-Password: Password123!
-```
-
 ### Backend Endpoints
 
 | Resource    | URL                              |
@@ -445,5 +432,4 @@ erDiagram
 - **Overdue is derived, not persisted.** The database stores only `Draft`, `Pending`, and `Paid`. `Overdue` is computed at read time when `status != Paid AND dueDate < today`. No background job is needed.
 - **No refresh tokens.** The access token is the only credential. Token refresh is out of scope for this assessment.
 - **No role-based authorization.** All authenticated users have the same permissions. RBAC is out of scope.
-- **No email delivery or payment integration.** Invoice creation and status transitions are data-only operations.
 - **Customer is embedded on the invoice.** Customer data (name, email, mobile, address) is stored as columns on `invoices` rather than a separate `customers` table. Invoices are self-contained records; there is no shared customer identity across invoices.

backend/src/config/app.config.ts

@@ -3,6 +3,7 @@ import Joi from 'joi';
 
 const DEFAULT_CORS_ORIGINS = [
   'http://localhost:3000',
+  'http://localhost:5173',
   'https://simpleinvoice.khangtran.dev',
 ];
 const DEFAULT_CORS_ORIGIN = DEFAULT_CORS_ORIGINS.join(',');

frontend/README.md

@@ -8,11 +8,11 @@ React 19 + TypeScript + Vite frontend for the SimpleInvoice assessment applicati
 
 **What to look for:**
 
-- **Protected Routes & Authentication** - Login redirects to invoice list on success; all invoice routes require valid JWT; logout clears session. See `auth-context.tsx`, `ProtectedRoute.tsx`.
-- **Invoice List** - Paginated, searchable, filterable by status (Draft/Pending/Paid/Overdue), sortable by date/amount. List state lives in URL query params. See `InvoiceListPage.tsx`, `use-invoice-list-query.ts`.
-- **Invoice Detail** - Full invoice information, line items, totals, payment status. Includes a **print-to-PDF** feature that produces an A4 document without external dependencies. See `InvoiceDetailPage.tsx`, `InvoicePrintDocument.tsx`.
-- **Create Invoice** - Multi-field form with real-time validation and a live preview panel. Backend validates totals; frontend shows preview. One line item per assessment spec. See `CreateInvoiceForm.tsx`, `createInvoiceSchema.ts`.
-- **Runtime Response Validation** - Zod schemas validate all API responses at unsafe boundaries (login, invoice list/detail, create). Parsing errors are caught and logged. See `invoices.schema.ts`, `auth.schema.ts`, `parse-api-response.ts`.
+- **Protected Routes & Authentication** - Login redirects to invoice list on success; all invoice routes require valid JWT; logout clears session. See [`src/features/auth/auth-context.tsx`](./src/features/auth/auth-context.tsx), [`src/features/auth/components/ProtectedRoute.tsx`](./src/features/auth/components/ProtectedRoute.tsx).
+- **Invoice List** - Paginated, searchable, filterable by status (Draft/Pending/Paid/Overdue), sortable by date/amount. List state lives in URL query params. See [`src/features/invoices/list/InvoiceListPage.tsx`](./src/features/invoices/list/InvoiceListPage.tsx), [`src/features/invoices/list/invoice-list-query.schema.ts`](./src/features/invoices/list/invoice-list-query.schema.ts).
+- **Invoice Detail** - Full invoice information, line items, totals, payment status. Includes a **print-to-PDF** feature that produces an A4 document without external dependencies. See [`src/features/invoices/detail/InvoiceDetailPage.tsx`](./src/features/invoices/detail/InvoiceDetailPage.tsx), [`src/features/invoices/detail/components/InvoicePrintDocument.tsx`](./src/features/invoices/detail/components/InvoicePrintDocument.tsx).
+- **Create Invoice** - Multi-field form with real-time validation and a live preview panel. Backend validates totals; frontend shows preview. One line item per assessment spec. See [`src/features/invoices/create/CreateInvoiceForm.tsx`](./src/features/invoices/create/CreateInvoiceForm.tsx), [`src/features/invoices/schema/create-invoice.schema.ts`](./src/features/invoices/schema/create-invoice.schema.ts).
+- **Runtime Response Validation** - Zod schemas validate all API responses at unsafe boundaries (login, invoice list/detail, create). Parsing errors are caught and logged. See [`src/api/invoices.schema.ts`](./src/api/invoices.schema.ts), [`src/api/auth.schema.ts`](./src/api/auth.schema.ts), [`src/api/parse-api-response.ts`](./src/api/parse-api-response.ts).
 - **Comprehensive Tests** - tests cover form validation, hooks, utilities, component behavior, and runtime schema validation. MSW mocks backend; factories generate test data. Run `npm run test` for the full suite. See `frontend/src/**/*.test.ts`, `test/mocks/`.
 - **Feature-First Architecture** - Code organized by feature (`auth`, `invoices`) with feature-local domain logic, not by layer. Shared utilities live in `shared/`. See folder structure below.
 
@@ -329,8 +329,8 @@ const user = authFactory.build({ email: 'test@example.com' });
 - **A4-ready** - CSS handles page size, margins, breaks.
 
 **Implementation:**
-- `InvoicePrintDocument.tsx` - A4-sized hidden layout.
-- `index.css` - `@media print` rule hides app shell, shows print document.
+- [`src/features/invoices/detail/components/InvoicePrintDocument.tsx`](./src/features/invoices/detail/components/InvoicePrintDocument.tsx) - A4-sized hidden layout.
+- [`src/index.css`](./src/index.css) - `@media print` rule hides app shell, shows print document.
 - `page-break-inside: avoid` prevents table/totals from splitting across pages.
 
 ---