Improve professional appearance: logo, favicon, and remove emoji icons

1. Added original favicon
   - Copied favicon.svg from original frontend
   - Added favicon reference to layout metadata
   - Professional icon with brand colors

2. Updated logo in navigation
   - Replaced emoji with proper SVG logo from original design
   - Uses circular target design with crosshairs
   - Matches brand identity with coral accent color

3. Removed emoji icons throughout app for professional look
   - Removed 📍 (location pin) from school locations
   - Removed 🏫 (school building) from school types
   - Removed 🔢 from URN labels and section headings
   - Kept meaningful symbols (✓, +) in buttons only
   - Updated map popup button color to brand coral (#e07256)

Components updated:
- Navigation: Professional SVG logo
- HomeView: Clean location banner
- SchoolDetailView: No decorative emojis in metadata
- ComparisonView: Text-only school information
- SchoolSearchModal: Clean school listings
- LeafletMapInner: Professional map popups

Result: More polished, professional appearance suitable for
educational data platform

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

nextjs-app/components/SchoolSearchModal.tsx

@@ -112,10 +112,10 @@ export function SchoolSearchModal({ isOpen, onClose }: SchoolSearchModalProps) {
                   <div className={styles.schoolName}>{school.school_name}</div>
                   <div className={styles.schoolMeta}>
                     {school.local_authority && (
-                      <span>📍 {school.local_authority}</span>
+                      <span>{school.local_authority}</span>
                     )}
                     {school.school_type && (
-                      <span>🏫 {school.school_type}</span>
+                      <span>{school.school_type}</span>
                     )}
                   </div>
                 </div>