feat: Kunden archivieren + Ticket-Status-Checkbox-Filter

Kunden:
- Neues Feld customers.archived; Archivieren/Wiederherstellen-Button in der
  Kundendetailseite, 'Archiviert'-Badge
- CustomersPage: vierter Filter-Tab 'Archiviert'; archivierte Kunden aus
  Alle/Leads/Feste Kunden ausgeblendet, nur im Archiv-Tab sichtbar

Tickets:
- Status-Mehrfachauswahl per Checkbox im Filterbereich; Default alle Status
  ausser 'Closed' (= archiviert). 'Standard' / 'Alle inkl. Archiv' Shortcuts
- useWorkorders: Statusfilter serverseitig via Query.equal(array) statt
  Client-Filter nach dem Limit (behebt Bug, bei dem archivierte Tickets die
  neuesten Slots belegten und aktive verdraengten)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/pages/CustomerDetailPage.jsx

@@ -1,6 +1,6 @@
 import { useState, useEffect, useCallback } from 'react'
 import { useParams, Link } from 'react-router-dom'
-import { FaSpinner, FaStar, FaArrowLeft, FaFloppyDisk, FaArrowUp, FaKey, FaArrowUpRightFromSquare } from 'react-icons/fa6'
+import { FaSpinner, FaStar, FaArrowLeft, FaFloppyDisk, FaArrowUp, FaKey, FaArrowUpRightFromSquare, FaBoxArchive, FaBoxOpen } from 'react-icons/fa6'
 import { databases, DATABASE_ID, COLLECTIONS, Query } from '../lib/appwrite'
 import { PageHeader, Card, Button, Badge, Tabs, EmptyState, Field } from '../components/ui'
 import { StatusPill, PriorityPill } from '../components/ui/StatusPill'
@@ -10,7 +10,7 @@ import AssignedProjectCard from '../components/AssignedProjectCard'
 import CopyableCredential, { getCustomerPortalPassword } from '../components/CopyableCredential'
 import { updateCustomerWithPortalAccess } from '../lib/customerAdminApi'
 import { useWebsiteProjects } from '../hooks/useWebsiteProjects'
-import { customerStage, isInvoiceReady, upgradeToCustomer, syncCustomerToNinja } from '../lib/leads'
+import { customerStage, isArchived, isInvoiceReady, setCustomerArchived, upgradeToCustomer, syncCustomerToNinja } from '../lib/leads'
 
 const PORTAL_URL = 'https://project.webklar.com'
 
@@ -47,8 +47,14 @@ export default function CustomerDetailPage() {
   if (error || !customer) return <div className="page"><EmptyState title="Kunde nicht gefunden" hint={error} action={<Button as={Link} to="/customers"><FaArrowLeft /> Zurueck</Button>} /></div>
 
   const stage = customerStage(customer)
+  const archived = isArchived(customer)
   const syntheticTicket = { customerId: customer.$id, customerName: customer.name, woid: '' }
 
+  const toggleArchived = async () => {
+    await setCustomerArchived(customer, !archived)
+    await load()
+  }
+
   return (
     <div className="page">
       <PageHeader
@@ -59,10 +65,18 @@ export default function CustomerDetailPage() {
             {stage === 'lead' && <Badge tone="warn" dot>Lead</Badge>}
             {stage === 'customer' && <Badge tone="ok" dot>Fester Kunde</Badge>}
             {stage === 'lost' && <Badge tone="muted">Abgesagt</Badge>}
+            {archived && <Badge tone="muted"><FaBoxArchive /> Archiviert</Badge>}
           </span>
         }
         subtitle={[customer.location, customer.email, customer.phone].filter(Boolean).join(' <20> ')}
-        actions={<Button variant="ghost" as={Link} to="/customers"><FaArrowLeft /> Alle Kunden</Button>}
+        actions={
+          <>
+            <Button variant="ghost" onClick={toggleArchived}>
+              {archived ? <><FaBoxOpen /> Wiederherstellen</> : <><FaBoxArchive /> Archivieren</>}
+            </Button>
+            <Button variant="ghost" as={Link} to="/customers"><FaArrowLeft /> Alle Kunden</Button>
+          </>
+        }
       />
 
       <Tabs tabs={TABS} active={tab} onChange={setTab} />