refactor: remove 473 lines of dead code across 5 SDK modules

- obligations: unused vendors state/fetch, unreachable filter==='ai' path
- tom: unused vendorControlsLoading state, unused bulkUpdateTOMs import
- loeschfristen: unused BASELINE_TEMPLATES imports, sdk hook, managingLegalHolds state
- vvt: unused apiGetCompleteness/apiGetLibrary, 7 unused VVTLib* interfaces
- vendor-compliance: 11 unused context methods, 6 unused selector hooks, ContractUploadData type

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

admin-compliance/app/sdk/obligations/page.tsx

@@ -588,17 +588,6 @@ export default function ObligationsPage() {
   const [profiling, setProfiling] = useState(false)
   const [applicableRegs, setApplicableRegs] = useState<ApplicableRegulation[]>([])
   const [activeTab, setActiveTab] = useState<Tab>('uebersicht')
-  const [vendors, setVendors] = useState<Array<{id: string, name: string, role: string}>>([])
-
-  useEffect(() => {
-    fetch('/api/sdk/v1/vendor-compliance/vendors?limit=500')
-      .then(r => r.ok ? r.json() : null)
-      .then(data => {
-        const items = data?.data?.items || []
-        setVendors(items.map((v: any) => ({ id: v.id, name: v.name, role: v.role })))
-      })
-      .catch(() => {})
-  }, [])
 
   // Compliance check result — auto-computed when obligations change
   const complianceResult = useMemo<ObligationComplianceCheckResult | null>(() => {
@@ -777,9 +766,6 @@ export default function ObligationsPage() {
   const stepInfo = STEP_EXPLANATIONS['obligations']
 
   const filteredObligations = obligations.filter(o => {
-    if (filter === 'ai') {
-      if (!o.source.toLowerCase().includes('ai')) return false
-    }
     if (regulationFilter !== 'all') {
       const src = o.source?.toLowerCase() || ''
       const key = regulationFilter.toLowerCase()