refactor: remove legacy permission system, use only feature-overrides

AdminPanel.jsx:
- Removed ai_enabled, ai_limit_day, export_enabled UI
- Kept only role selection (Admin/User)
- Added link to Feature-Overrides page
- Simplified perms state to only role
- Changed display to show tier and email

AdminUserRestrictionsPage.jsx:
- Removed legacy system warning
- Clean interface, no confusion

Result:
- ONE consistent permission system (feature-overrides)
- Clear separation: role in AdminPanel, limits in Feature-Overrides
- No data migration needed (no old users exist)
- System ready for production

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/pages/AdminPanel.jsx

@@ -143,9 +143,6 @@ function EmailEditor({ profileId, currentEmail, onSaved }) {
 function ProfileCard({ profile, currentId, onRefresh }) {
   const [expanded, setExpanded] = useState(false)
   const [perms, setPerms] = useState({
-    ai_enabled:     profile.ai_enabled ?? 1,
-    ai_limit_day:   profile.ai_limit_day || '',
-    export_enabled: profile.export_enabled ?? 1,
     role: profile.role || 'user',
   })
   const [saving, setSaving] = useState(false)
@@ -157,9 +154,6 @@ function ProfileCard({ profile, currentId, onRefresh }) {
     setSaving(true)
     try {
       await api.adminSetPermissions(profile.id, {
-        ai_enabled:     perms.ai_enabled,
-        ai_limit_day:   perms.ai_limit_day ? parseInt(perms.ai_limit_day) : null,
-        export_enabled: perms.export_enabled,
         role: perms.role,
       })
       await onRefresh()
@@ -196,9 +190,8 @@ function ProfileCard({ profile, currentId, onRefresh }) {
             {isSelf && <span style={{fontSize:10,color:'var(--text3)'}}>Du</span>}
           </div>
           <div style={{fontSize:11,color:'var(--text3)'}}>
-            KI: {profile.ai_enabled?`✓${profile.ai_limit_day?` (max ${profile.ai_limit_day}/Tag)`:''}` : '✗'} ·
-            Export: {profile.export_enabled?'✓':'✗'} ·
-            Calls heute: {profile.ai_calls_today||0}
+            Tier: {profile.tier || 'free'} ·
+            Email: {profile.email || 'nicht gesetzt'}
           </div>
         </div>
         <div style={{display:'flex',gap:6}}>
@@ -233,23 +226,19 @@ function ProfileCard({ profile, currentId, onRefresh }) {
                 </button>
               ))}
             </div>
-          </div>
-
-          <Toggle value={!!perms.ai_enabled} onChange={v=>setPerms(p=>({...p,ai_enabled:v?1:0}))} label="KI-Analysen erlaubt"/>
-          {!!perms.ai_enabled && (
-            <div className="form-row" style={{paddingTop:6}}>
-              <label className="form-label" style={{fontSize:12}}>Max. KI-Calls/Tag</label>
-              <input type="number" className="form-input" style={{width:70}} min={1} max={100}
-                placeholder="∞" value={perms.ai_limit_day}
-                onChange={e=>setPerms(p=>({...p,ai_limit_day:e.target.value}))}/>
-              <span className="form-unit" style={{fontSize:11}}>/Tag</span>
-            </div>
-          )}
-          <Toggle value={!!perms.export_enabled} onChange={v=>setPerms(p=>({...p,export_enabled:v?1:0}))} label="Daten-Export erlaubt"/>
-
-          <button className="btn btn-primary btn-full" style={{marginTop:10}} onClick={savePerms} disabled={saving}>
-            {saving?'Speichern…':'Berechtigungen speichern'}
+            <button className="btn btn-primary btn-full" style={{marginTop:8}} onClick={savePerms} disabled={saving}>
+              {saving?'Speichern…':'Rolle speichern'}
             </button>
+          </div>
+
+          {/* Feature-Overrides */}
+          <div style={{marginBottom:12,padding:10,background:'var(--accent-light)',borderRadius:6,fontSize:12}}>
+            <strong>Feature-Limits:</strong> Nutze die neue{' '}
+            <Link to="/admin/user-restrictions" style={{color:'var(--accent-dark)',fontWeight:600}}>
+              User Feature-Overrides
+            </Link>{' '}
+            Seite um individuelle Limits zu setzen.
+          </div>
 
           {/* Email */}
           <div style={{marginTop:12,paddingTop:12,borderTop:'1px solid var(--border)'}}>

frontend/src/pages/AdminUserRestrictionsPage.jsx

@@ -252,24 +252,6 @@ export default function AdminUserRestrictionsPage() {
         </div>
       </div>
 
-      {/* Legacy System Warning */}
-      <div style={{
-        padding: 12, background: '#FFF3CD', borderRadius: 8,
-        marginBottom: 16, fontSize: 12, color: '#856404',
-        display: 'flex', gap: 8, alignItems: 'flex-start',
-        border: '1px solid #FFE69C'
-      }}>
-        <AlertCircle size={16} style={{ marginTop: 2, flexShrink: 0 }} />
-        <div>
-          <strong>⚠️ Legacy-System aktiv:</strong> In der Benutzerverwaltung existiert noch das alte Berechtigungssystem
-          ("KI-Analysen erlaubt", "Max. KI-Calls/Tag", "Daten-Export erlaubt").
-          Diese Einstellungen können mit den neuen Feature-Overrides kollidieren.
-          <strong> Das neue Feature-Override-System hat Vorrang.</strong>
-          <br/><br/>
-          <strong>Empfehlung:</strong> Verwende nur noch Feature-Overrides. Das alte System wird in einer zukünftigen Version entfernt.
-        </div>
-      </div>
-
       {/* Messages */}
       {error && (
         <div style={{