feat: add price filter and dynamic slider to catalog

- Implemented JavaScript-based price slider for catalog filtering
- Updated catalog views to handle min/max price inputs and compute slider bounds
- Enhanced templates (`index.html`, `side-bar.html`) with filtering form and updated URLs
- Added CSS for price slider styling and form layout
- Introduced utility functions for URL building and price parsing
- Expanded tests for price filtering, sliders, and sidebar active states
- Updated context processor and header for dynamic navigation with price filters

.env.example

@@ -7,6 +7,7 @@ ALLOWED_HOSTS=example.com,www.example.com
 CSRF_TRUSTED_ORIGINS=https://example.com,https://www.example.com
 USE_X_FORWARDED_HOST=true
 SECURE_PROXY_SSL_HEADER=HTTP_X_FORWARDED_PROTO,https
+SECURE_REFERRER_POLICY=strict-origin-when-cross-origin
 SITE_NAME=SantehRay
 LOGIN_URL=/users/login/
 LOGIN_REDIRECT_URL=/users/profile/