docs: update README and contributing guidance

Co-authored-by: GizzZmo <8039975+GizzZmo@users.noreply.github.com>

Author: Copilot

CONTRIBUTING.md

@@ -19,6 +19,7 @@ Thank you for your interest in contributing! Here are some guidelines to help yo
 
 ## Build, Lint, and Test
 
+- Use Node.js 20.x (npm 10.x) to match CI.
 - Install dependencies with `npm run install:all`.
 - Build shared types first: `npx tsc --build src/types`.
 - Run the full build: `npm run build:all`.

README.md

@@ -119,8 +119,8 @@ This project is structured as a monorepo containing both a frontend (React/TypeS
 
 ### Prerequisites
 
-- Node.js (v16 or higher)
-- npm (v7 or higher)
+- Node.js 20.x
+- npm 10.x (bundled with Node.js 20)
 
 ### Installation
 
@@ -132,15 +132,9 @@ This project is structured as a monorepo containing both a frontend (React/TypeS
 
 2. **Install dependencies:**
    ```bash
-   # Install root dependencies
-   npm install
-
-   # Install server dependencies
-   npm install --prefix server
-
-   # Install client dependencies (if using alternative client)
-   npm install --prefix client
+   npm run install:all
    ```
+   This installs root, server, and client dependencies in one step.
 
 ### Development
 
@@ -166,9 +160,16 @@ This project is structured as a monorepo containing both a frontend (React/TypeS
    - Frontend: http://localhost:3000 (or the port shown in terminal)
    - Backend API: http://localhost:3001 (or configured port)
 
+### Environment Variables
+
+The frontend is built with Vite, so environment variables must be read from `import.meta.env` (for example, `import.meta.env.VITE_API_URL`). Using `process.env` will not work in the browser bundle.
+
 ### Building for Production
 
 ```bash
+# Build shared types first (required for server compilation)
+npx tsc --build src/types
+
 # Build all components
 npm run build:all
 
@@ -188,6 +189,15 @@ npm run lint:all
 npm run preview
 ```
 
+## Validation Checklist
+
+- Build shared types: `npx tsc --build src/types`
+- Full build: `npm run build:all`
+- Lint: `npm run lint:all`
+- Manual smoke test:
+  - Start backend: `npm run dev:server` and verify `curl http://localhost:3001/health` returns `{"status":"ok"}`.
+  - Start frontend: `npm run dev:frontend`, visit http://localhost:3000, and navigate between Dashboard, Master Prompt Editor, and Advanced AI Toolkit. Press `Ctrl + /` to confirm the shortcuts panel appears.
+
 ## Security & Performance
 
 This project implements comprehensive security measures and performance optimizations. For detailed information, see [SECURITY_OPTIMIZATION_REPORT.md](SECURITY_OPTIMIZATION_REPORT.md).