feat(iace): hazard block view — parent/child grouping

Backend:
- hazard_blocks.go: ComputeHazardBlocks() groups hazards by category +
  component + zone. Parent = highest risk in group. Children covered by
  parent's measures are flagged (no separate assessment needed).
- iace_handler_blocks.go: GET /projects/:id/hazard-blocks endpoint
  with summary stats (blocks, covered children, assessments saved)

Frontend:
- HazardBlockView.tsx: Expandable block view with summary cards,
  parent-child hierarchy, coverage badges, and "abgedeckt" indicators
- hazards/page.tsx: New "Bloecke" tab alongside "Hazard-Liste" and
  "Risikobewertung"

No database schema changes — grouping is computed at runtime.

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

admin-compliance/app/sdk/iace/[projectId]/hazards/page.tsx

@@ -4,6 +4,7 @@ import React, { useState, useMemo, useCallback } from 'react'
 import { useParams } from 'next/navigation'
 import { HazardForm } from './_components/HazardForm'
 import { HazardTable } from './_components/HazardTable'
+import { HazardBlockView } from './_components/HazardBlockView'
 import { RiskAssessmentTable } from './_components/RiskAssessmentTable'
 import { ResidualRiskPanel, getResidualStatus } from './_components/ResidualRiskPanel'
 import type { ResidualFilter } from './_components/ResidualRiskPanel'
@@ -12,7 +13,7 @@ import { AutoSuggestPanel } from './_components/AutoSuggestPanel'
 import { CustomHazardModal } from './_components/CustomHazardModal'
 import { useHazards } from './_hooks/useHazards'
 
-type ViewMode = 'list' | 'risk'
+type ViewMode = 'list' | 'risk' | 'blocks'
 
 export default function HazardsPage() {
   const params = useParams()
@@ -69,6 +70,10 @@ export default function HazardsPage() {
               className={`px-3 py-1.5 font-medium transition-colors border-l border-gray-200 dark:border-gray-600 ${view === 'risk' ? 'bg-purple-600 text-white' : 'bg-white dark:bg-gray-800 text-gray-600 dark:text-gray-400 hover:bg-gray-50'}`}>
               Risikobewertung
             </button>
+            <button onClick={() => setView('blocks')}
+              className={`px-3 py-1.5 font-medium transition-colors border-l border-gray-200 dark:border-gray-600 ${view === 'blocks' ? 'bg-purple-600 text-white' : 'bg-white dark:bg-gray-800 text-gray-600 dark:text-gray-400 hover:bg-gray-50'}`}>
+              Bloecke
+            </button>
           </div>
         </div>
         <div className="flex items-center gap-2">
@@ -172,6 +177,8 @@ export default function HazardsPage() {
             <RiskAssessmentTable projectId={projectId} hazards={filteredHazards}
               onReassess={h.refetch} decisions={decisions} onDecision={handleDecision} />
           </>
+        ) : view === 'blocks' ? (
+          <HazardBlockView />
         ) : (
           <HazardTable hazards={h.hazards} lifecyclePhases={h.lifecyclePhases} onDelete={h.handleDelete} />
         )