feat: Use-Cases/UCCA Module auf 100% — Interface Fix, Search/Offset/Total, Explain/Export, Edit-Mode

Kritische Bug Fixes:
- [id]/page.tsx: FullAssessment Interface repariert (nested result → flat fields)
- resultForCard baut explizit aus flachen Assessment-Feldern (feasibility, risk_score etc.)
- Use-Case-Text-Pfad: assessment.intake?.use_case_text statt assessment.use_case_text
- rule_code/code Mapping beim Übergeben an AssessmentResultCard

Backend (A2+A3):
- store.go: AssessmentFilters um Search + Offset erweitert
- ListAssessments: COUNT-Query (total), ILIKE-Search auf title, OFFSET-Pagination
- ListAssessments Signatur: ([]Assessment, int, error)
- Handler: search/offset aus Query-Params, total in Response
- import "strconv" hinzugefügt

Neue Features:
- KI-Erklärung Button (POST /explain) mit lila Erklärungsbox
- Export-Buttons Markdown + JSON (Download-Links)
- Edit-Mode in new/page.tsx: useSearchParams(?edit=id), Form vorausfüllen
- Bedingte PUT/POST Logik; nach Edit → Detail-Seite Redirect
- Suspense-Wrapper für useSearchParams (Next.js 15 Requirement)

Backend Edit:
- store.go: UpdateAssessment() Methode (UPDATE-Query)
- ucca_handlers.go: UpdateAssessment Handler (re-evaluiert Intake)
- main.go: PUT /ucca/assessments/:id Route registriert

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

admin-compliance/app/(sdk)/sdk/use-cases/new/page.tsx

@@ -1,7 +1,7 @@
 'use client'
 
-import React, { useState } from 'react'
-import { useRouter } from 'next/navigation'
+import React, { useState, useEffect, Suspense } from 'react'
+import { useRouter, useSearchParams } from 'next/navigation'
 import { AssessmentResultCard } from '@/components/sdk/use-case-assessment/AssessmentResultCard'
 
 // =============================================================================
@@ -38,10 +38,15 @@ const DOMAINS = [
 // MAIN COMPONENT
 // =============================================================================
 
-export default function NewUseCasePage() {
+function NewUseCasePageInner() {
   const router = useRouter()
+  const searchParams = useSearchParams()
+  const editId = searchParams.get('edit')
+  const isEditMode = !!editId
+
   const [currentStep, setCurrentStep] = useState(1)
   const [isSubmitting, setIsSubmitting] = useState(false)
+  const [editLoading, setEditLoading] = useState(false)
   const [result, setResult] = useState<unknown>(null)
   const [error, setError] = useState<string | null>(null)
 
@@ -93,6 +98,52 @@ export default function NewUseCasePage() {
     setForm(prev => ({ ...prev, ...updates }))
   }
 
+  // Pre-fill form when in edit mode
+  useEffect(() => {
+    if (!editId) return
+    setEditLoading(true)
+    fetch(`/api/sdk/v1/ucca/assessments/${editId}`)
+      .then(r => r.json())
+      .then(data => {
+        const intake = data.intake || {}
+        setForm({
+          title: data.title || '',
+          use_case_text: intake.use_case_text || '',
+          domain: data.domain || 'general',
+          personal_data: intake.data_types?.personal_data || false,
+          special_categories: intake.data_types?.article_9_data || false,
+          minors_data: intake.data_types?.minor_data || false,
+          health_data: intake.data_types?.health_data || false,
+          biometric_data: intake.data_types?.biometric_data || false,
+          financial_data: intake.data_types?.financial_data || false,
+          purpose_profiling: intake.purpose?.profiling || false,
+          purpose_automated_decision: intake.purpose?.automated_decision || intake.purpose?.decision_making || false,
+          purpose_marketing: intake.purpose?.marketing || false,
+          purpose_analytics: intake.purpose?.analytics || false,
+          purpose_service_delivery: intake.purpose?.service_delivery || intake.purpose?.customer_support || false,
+          automation: intake.automation || 'assistive',
+          hosting_provider: intake.hosting?.provider || 'self_hosted',
+          hosting_region: intake.hosting?.region || 'eu',
+          model_rag: intake.model_usage?.rag || false,
+          model_finetune: intake.model_usage?.finetune || false,
+          model_training: intake.model_usage?.training || false,
+          model_inference: intake.model_usage?.inference ?? true,
+          legal_basis: intake.legal_basis || 'consent',
+          international_transfer: intake.international_transfer?.enabled || false,
+          transfer_countries: intake.international_transfer?.countries || [],
+          transfer_mechanism: intake.international_transfer?.mechanism || 'none',
+          retention_days: intake.retention?.days || 90,
+          retention_purpose: intake.retention?.purpose || '',
+          has_dpa: intake.contracts?.has_dpa || false,
+          has_aia_documentation: intake.contracts?.has_aia_documentation || false,
+          has_risk_assessment: intake.contracts?.has_risk_assessment || false,
+          subprocessors: intake.contracts?.subprocessors || '',
+        })
+      })
+      .catch(() => {})
+      .finally(() => setEditLoading(false))
+  }, [editId])
+
   const handleSubmit = async () => {
     setIsSubmitting(true)
     setError(null)
@@ -146,8 +197,13 @@ export default function NewUseCasePage() {
         store_raw_text: true,
       }
 
-      const response = await fetch('/api/sdk/v1/ucca/assess', {
-        method: 'POST',
+      const url = isEditMode
+        ? `/api/sdk/v1/ucca/assessments/${editId}`
+        : '/api/sdk/v1/ucca/assess'
+      const method = isEditMode ? 'PUT' : 'POST'
+
+      const response = await fetch(url, {
+        method,
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify(intake),
       })
@@ -157,6 +213,11 @@ export default function NewUseCasePage() {
         throw new Error(errData?.error || `HTTP ${response.status}`)
       }
 
+      if (isEditMode) {
+        router.push(`/sdk/use-cases/${editId}`)
+        return
+      }
+
       const data = await response.json()
       setResult(data)
     } catch (err) {
@@ -201,12 +262,23 @@ export default function NewUseCasePage() {
     <div className="max-w-3xl mx-auto space-y-6">
       {/* Header */}
       <div>
-        <h1 className="text-2xl font-bold text-gray-900">Neues Use Case Assessment</h1>
+        <h1 className="text-2xl font-bold text-gray-900">
+          {isEditMode ? 'Assessment bearbeiten' : 'Neues Use Case Assessment'}
+        </h1>
         <p className="mt-1 text-gray-500">
-          Beschreiben Sie Ihren KI-Anwendungsfall Schritt fuer Schritt
+          {isEditMode
+            ? 'Angaben anpassen und Assessment neu bewerten'
+            : 'Beschreiben Sie Ihren KI-Anwendungsfall Schritt fuer Schritt'}
         </p>
       </div>
 
+      {/* Edit loading indicator */}
+      {editLoading && (
+        <div className="bg-purple-50 border border-purple-200 rounded-lg p-4 text-purple-700 text-sm">
+          Lade Assessment-Daten...
+        </div>
+      )}
+
       {/* Step Indicator */}
       <div className="flex items-center gap-2">
         {WIZARD_STEPS.map((step, idx) => (
@@ -591,7 +663,7 @@ export default function NewUseCasePage() {
                 Bewerte...
               </>
             ) : (
-              'Assessment starten'
+              isEditMode ? 'Speichern & neu bewerten' : 'Assessment starten'
             )}
           </button>
         )}
@@ -599,3 +671,11 @@ export default function NewUseCasePage() {
     </div>
   )
 }
+
+export default function NewUseCasePage() {
+  return (
+    <Suspense fallback={<div className="flex items-center justify-center h-64 text-gray-500">Lade...</div>}>
+      <NewUseCasePageInner />
+    </Suspense>
+  )
+}