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/Admin/AppConfigDetailPage.tsx

@@ -1,5 +1,6 @@
 import { useEffect, useState, useMemo } from 'react';
 import { useParams, useNavigate } from 'react-router';
+import { ArrowLeft, Pencil, X } from 'lucide-react';
 import {
   Button, SectionHeader, MonoText, Badge, DataTable, Spinner, Toggle, useToast,
 } from '@cameleer/design-system';
@@ -248,7 +249,7 @@ export default function AppConfigDetailPage() {
         if (row.captureMode === null) return null;
         return (
           <button className={styles.removeBtn} title="Remove" onClick={() => updateTracedProcessor(row.processorId, 'REMOVE')}>
-            &times;
+            <X size={14} />
           </button>
         );
       },
@@ -303,7 +304,7 @@ export default function AppConfigDetailPage() {
   return (
     <div className={styles.page}>
       <div className={styles.toolbar}>
-        <button className={styles.backBtn} onClick={() => navigate('/admin/appconfig')}>&larr; Back</button>
+        <button className={styles.backBtn} onClick={() => navigate('/admin/appconfig')}><ArrowLeft size={14} /> Back</button>
         {editing ? (
           <div className={styles.toolbarActions}>
             <Button onClick={handleSave} disabled={updateConfig.isPending}>
@@ -312,7 +313,7 @@ export default function AppConfigDetailPage() {
             <button className={styles.cancelBtn} onClick={cancelEditing}>Cancel</button>
           </div>
         ) : (
-          <button className={styles.editBtn} onClick={startEditing}>&#x270E; Edit</button>
+          <button className={styles.editBtn} onClick={startEditing}><Pencil size={14} /> Edit</button>
         )}
       </div>