feat: Set up SessionMiddleware and Jinja2 Template Configuration

- Add SECRET_KEY environment variable and .env file for session management
- Configure SessionMiddleware with FastAPI for user session handling
- Set up Jinja2 template engine with template directory configuration
- Mount static files directory for CSS, JS, and image assets
- Create comprehensive base.html template with Bootstrap 5 CDN
- Add Bootstrap Icons and custom styling support
- Include responsive navigation with user authentication state
- Create placeholder CSS and JavaScript files for customization
- Add aiofiles dependency for static file serving

This establishes the web framework foundation with session management
and templating system ready for frontend development.

static/css/custom.css

@@ -0,0 +1,51 @@
+/* Custom CSS for Delphi Database */
+
+/* Additional styles can be added here */
+body {
+    background-color: #f8f9fa;
+}
+
+/* Custom navbar styles */
+.navbar-brand {
+    font-weight: bold;
+}
+
+/* Custom card styles */
+.card {
+    box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
+    border: 1px solid rgba(0, 0, 0, 0.125);
+}
+
+/* Custom button styles */
+.btn-primary {
+    background-color: #0d6efd;
+    border-color: #0d6efd;
+}
+
+.btn-primary:hover {
+    background-color: #0b5ed7;
+    border-color: #0a58ca;
+}
+
+/* Custom form styles */
+.form-control:focus {
+    border-color: #86b7fe;
+    box-shadow: 0 0 0 0.25rem rgba(13, 110, 253, 0.25);
+}
+
+/* Custom table styles */
+.table th {
+    background-color: #f8f9fa;
+    border-bottom: 2px solid #dee2e6;
+}
+
+/* Custom alert styles */
+.alert {
+    border: none;
+    border-radius: 0.375rem;
+}
+
+/* Custom footer styles */
+footer {
+    margin-top: auto;
+}