Initial project setup with core app files

Add main React app, settings modal, constants, types, and service for LLM prompt optimization. Includes test suite, configuration files, CI workflow, documentation, and example environment variables. Supports Gemini and OpenAI-compatible APIs, with prompt templates, history, and favorites features.

Author: nsalvacao

.env.example

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+# ==============================================================================
+# LLM PROMPT OPTIMIZER - ENVIRONMENT VARIABLES
+# ==============================================================================
+#
+# This file contains example environment variables for the application.
+# Copy this file to `.env.local` and fill in your actual API keys.
+#
+# IMPORTANT: Never commit `.env.local` to version control!
+#
+# ==============================================================================
+
+# ------------------------------------------------------------------------------
+# GEMINI API KEY (Primary Provider)
+# ------------------------------------------------------------------------------
+#
+# Get your free Gemini API key at: https://aistudio.google.com/apikey
+#
+# The application uses Gemini 2.5 Pro by default to optimize prompts.
+# This is required if you're using the default Gemini provider.
+#
+GEMINI_API_KEY=your_gemini_api_key_here
+
+# ------------------------------------------------------------------------------
+# ALTERNATIVE: OPENAI-COMPATIBLE API
+# ------------------------------------------------------------------------------
+#
+# If you prefer to use an OpenAI-compatible API instead of Gemini,
+# you can configure it via the Settings modal (gear icon) in the app.
+#
+# Required settings (configured in-app):
+# - Base URL: e.g., https://api.openai.com/v1
+# - API Key: Your OpenAI API key
+# - Model: e.g., gpt-4, gpt-3.5-turbo
+#
+# Note: These settings are stored in browser localStorage, not in .env
+#
+# ------------------------------------------------------------------------------

.github/workflows/ci.yml

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+name: CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [18.x, 20.x, 22.x]
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Setup Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v4
+      with:
+        node-version: ${{ matrix.node-version }}
+        cache: 'npm'
+
+    - name: Install dependencies
+      run: npm ci
+
+    - name: Run tests
+      run: npm test
+
+    - name: Build project
+      run: npm run build
+
+    - name: Upload build artifacts
+      if: matrix.node-version == '20.x'
+      uses: actions/upload-artifact@v4
+      with:
+        name: dist
+        path: dist/
+        retention-days: 7

.gitignore

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+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+lerna-debug.log*
+
+# Dependencies
+node_modules
+
+# Build outputs
+dist
+dist-ssr
+build
+*.local
+
+# Environment variables & sensitive files
+.env
+.env.local
+.env.production
+.env.*.local
+*.key
+*.pem
+*secret*
+
+# Archives (may contain sensitive data)
+*.zip
+*.tar.gz
+*.rar
+
+# Editor directories and files
+.vscode/*
+!.vscode/extensions.json
+.idea
+.DS_Store
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?
+
+# OS files
+Thumbs.db
+.DS_Store
+
+# Testing
+coverage
+.nyc_output
+
+# Optional npm cache directory
+.npm
+
+# Optional eslint cache
+.eslintcache
+/Dev
+CLAUDE.md
+AGENTS.md
+.claude/settings.local.json
+GEMINI.md

App.test.tsx

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+import { describe, it, expect } from 'vitest'
+import { render, screen } from '@testing-library/react'
+import App from './App'
+
+describe('App Smoke Tests', () => {
+    it('should render without crashing', () => {
+        render(<App />)
+        expect(document.body).toBeDefined()
+    })
+
+    it('should display the main title', () => {
+        render(<App />)
+        const title = screen.getByText(/LLM Prompt Optimizer/i)
+        expect(title).toBeInTheDocument()
+    })
+
+    it('should display the optimize button', () => {
+        render(<App />)
+        const button = screen.getByRole('button', { name: /optimize/i })
+        expect(button).toBeInTheDocument()
+    })
+
+    it('should have a textarea for prompt input', () => {
+        render(<App />)
+        const textarea = screen.getByPlaceholderText(/enter your prompt/i)
+        expect(textarea).toBeInTheDocument()
+    })
+
+    it('should display all LLM selection buttons', () => {
+        render(<App />)
+        expect(screen.getByText(/Gemini/i)).toBeInTheDocument()
+        expect(screen.getByText(/Anthropic/i)).toBeInTheDocument()
+        expect(screen.getByText(/OpenAI/i)).toBeInTheDocument()
+        expect(screen.getByText(/Meta/i)).toBeInTheDocument()
+    })
+
+    it('should display template section', () => {
+        render(<App />)
+        const templateHeader = screen.getByText(/Start with a Template/i)
+        expect(templateHeader).toBeInTheDocument()
+    })
+
+    it('should display history sidebar', () => {
+        render(<App />)
+        const historyTab = screen.getByRole('button', { name: /history/i })
+        const favoritesTab = screen.getByRole('button', { name: /favorites/i })
+        expect(historyTab).toBeInTheDocument()
+        expect(favoritesTab).toBeInTheDocument()
+    })
+})