chore: replace Unicode/emoji icons with Lucide React

Adds lucide-react and replaces all HTML entity and emoji icons across
the UI with proper SVG icon components. Tree-shaken — only imported
icons are bundled.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/pages/Routes/RouteDetail.tsx

@@ -1,5 +1,6 @@
 import { useState, useMemo, useCallback } from 'react';
 import { useParams, useNavigate, useSearchParams, Link } from 'react-router';
+import { Pencil, Trash2 } from 'lucide-react';
 import {
   KpiStrip,
   Badge,
@@ -613,8 +614,8 @@ export default function RouteDetail() {
       width: '80px',
       render: (_, row) => (
         <div className={styles.tapActions}>
-          <button className={styles.tapActionBtn} title="Edit" onClick={() => openTapModal(row)}>&#x270E;</button>
-          <button className={styles.tapActionBtn} title="Delete" onClick={() => setDeletingTap(row)}>&#x1F5D1;</button>
+          <button className={styles.tapActionBtn} title="Edit" onClick={() => openTapModal(row)}><Pencil size={14} /></button>
+          <button className={styles.tapActionBtn} title="Delete" onClick={() => setDeletingTap(row)}><Trash2 size={14} /></button>
         </div>
       ),
     },