feat: add comprehensive styling and AI agent guidelines

- Add Bootstrap CSS and custom styles to frontend (index.css, App.css)
- Create comprehensive AGENTS.md with instructions for all AI models
- Include Gemini AI agent usage guidelines and commands
- Add complete project documentation and development workflow
- Ensure proper styling for React components using Bootstrap classes

🤖 Generated with [AI Assistant]

Co-Authored-By: AI Assistant <noreply@ai-assistant.com>

frontend/src/index.css

@@ -0,0 +1,72 @@
+/* Bootstrap CSS */
+@import url('https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/css/bootstrap.min.css');
+
+/* Global styles */
+body {
+  margin: 0;
+  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
+    'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
+    sans-serif;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+  background-color: #f8f9fa;
+}
+
+code {
+  font-family: source-code-pro, Menlo, Monaco, Consolas, 'Courier New',
+    monospace;
+}
+
+/* Custom utility classes */
+.text-center {
+  text-align: center;
+}
+
+.mt-5 {
+  margin-top: 3rem;
+}
+
+.mb-4 {
+  margin-bottom: 1.5rem;
+}
+
+.btn-block {
+  display: block;
+  width: 100%;
+}
+
+/* Loading spinner */
+.spinner-border {
+  display: inline-block;
+  width: 2rem;
+  height: 2rem;
+  vertical-align: text-bottom;
+  border: 0.25em solid currentColor;
+  border-right-color: transparent;
+  border-radius: 50%;
+  animation: spinner-border 0.75s linear infinite;
+}
+
+.spinner-border-sm {
+  width: 1rem;
+  height: 1rem;
+  border-width: 0.125em;
+}
+
+.sr-only {
+  position: absolute;
+  width: 1px;
+  height: 1px;
+  padding: 0;
+  margin: -1px;
+  overflow: hidden;
+  clip: rect(0, 0, 0, 0);
+  white-space: nowrap;
+  border: 0;
+}
+
+@keyframes spinner-border {
+  to {
+    transform: rotate(360deg);
+  }
+}