feat(licenses): attribution renderer — Stufe 1 (overview) + Stufe 3 (SourceBadge)

Backend
- backend-compliance/compliance/api/licenses_routes.py: three endpoints
  built on the now-complete license_rule classification
  - GET  /api/compliance/licenses/overview
       global aggregation by rule + per-source breakdown (Stufe 1)
  - POST /api/compliance/licenses/aggregate
       per-control-set aggregation for PDF footer (Stufe 2) and
       tech-file appendix (Stufe 4) — consumed later
  - GET  /api/compliance/licenses/source-info/{control_uuid}
       single-control lookup for the inline source badge (Stufe 3)
- registered in api/__init__.py via the existing safe-import loader

Frontend
- app/sdk/licenses/page.tsx (Stufe 1): the /sdk/licenses overview page.
  Renders rule legend cards + per-rule source tables. Drives the
  /licenses footer link and gives auditors a one-page view of what
  licence classes the platform is operating under.
- components/sdk/SourceBadge.tsx (Stufe 3): reusable React component.
  Small R1/R2/R3 pill with click-expand tooltip showing source
  regulation + attribution string + render-full-text policy. Will be
  embedded into IACE hazards/mitigations, VVT items, DSFA controls in
  follow-up commits.

Two stages of the four-stage renderer are now ready. Stufe 2 (PDF
auto-footer) + Stufe 4 (tech-file appendix) follow once the existing
PDF generators are extended to call /licenses/aggregate.

admin-compliance/components/sdk/SourceBadge.tsx

@@ -0,0 +1,138 @@
+'use client'
+
+import { useEffect, useState } from 'react'
+
+// Stufe 3 of the Attribution Renderer (Task #23): an inline source
+// badge that any rendered control/hazard/measure can attach to itself.
+//
+// Visually a small license-rule pill (R1/R2/R3); on hover/click it
+// reveals the underlying regulation, license type, and — for Rule 2 —
+// the mandatory attribution string.
+//
+// Usage:
+//   <SourceBadge controlUuid={hazard.id} />
+//
+// The component lazily fetches /licenses/source-info/{uuid} on first
+// expand so the surrounding list view stays cheap.
+
+type SourceInfo = {
+  control_uuid: string
+  license_rule: number | null
+  license_label_de: string | null
+  attribution_required: boolean
+  render_full_text: boolean
+  regulation_id: string | null
+  regulation_name_de: string | null
+  license_type: string | null
+  attribution: string | null
+  source_url: string | null
+}
+
+const RULE_BADGE: Record<number, string> = {
+  1: 'bg-emerald-100 text-emerald-800 border-emerald-300',
+  2: 'bg-amber-100 text-amber-800 border-amber-300',
+  3: 'bg-slate-100 text-slate-700 border-slate-300',
+}
+
+const RULE_TITLE: Record<number, string> = {
+  1: 'R1 — wörtlich übernehmbar',
+  2: 'R2 — wörtlich mit Attribution',
+  3: 'R3 — nur Identifier zitieren',
+}
+
+interface SourceBadgeProps {
+  controlUuid: string
+  /** Optional: skip the fetch and render from already-known data. */
+  prefetched?: SourceInfo
+  /** Compact mode for tight UI rows (smaller pill). */
+  compact?: boolean
+}
+
+export function SourceBadge({ controlUuid, prefetched, compact }: SourceBadgeProps) {
+  const [data, setData] = useState<SourceInfo | null>(prefetched ?? null)
+  const [open, setOpen] = useState(false)
+  const [loading, setLoading] = useState(false)
+  const [error, setError] = useState<string | null>(null)
+
+  useEffect(() => {
+    if (!open || data) return
+    setLoading(true)
+    fetch(`/api/sdk/v1/compliance/licenses/source-info/${controlUuid}`)
+      .then((r) => (r.ok ? r.json() : Promise.reject(`HTTP ${r.status}`)))
+      .then(setData)
+      .catch((e) => setError(String(e)))
+      .finally(() => setLoading(false))
+  }, [open, data, controlUuid])
+
+  const rule = data?.license_rule ?? prefetched?.license_rule ?? null
+  const badgeClass = rule ? RULE_BADGE[rule] ?? RULE_BADGE[3] : 'bg-slate-100 text-slate-500 border-slate-200'
+  const sizeClass = compact ? 'text-[10px] px-1.5 py-0.5' : 'text-xs px-2 py-0.5'
+
+  return (
+    <span className="relative inline-block">
+      <button
+        type="button"
+        onClick={() => setOpen((v) => !v)}
+        className={`inline-flex items-center gap-1 rounded border font-medium ${sizeClass} ${badgeClass} hover:opacity-80 transition`}
+        title={rule ? RULE_TITLE[rule] : 'Lizenz unbekannt'}
+        aria-expanded={open}
+      >
+        <svg width="10" height="10" viewBox="0 0 16 16" fill="currentColor" aria-hidden>
+          <path d="M8 0a8 8 0 1 0 0 16A8 8 0 0 0 8 0Zm0 4.5a1 1 0 1 1 0 2 1 1 0 0 1 0-2ZM7 8h2v4.5H7V8Z" />
+        </svg>
+        {rule ? `R${rule}` : '?'}
+      </button>
+
+      {open && (
+        <div className="absolute left-0 mt-1 z-40 w-80 rounded-md border border-slate-200 bg-white shadow-lg p-3 text-xs">
+          {loading && <p className="text-slate-500">Lade Quellen-Info…</p>}
+          {error && <p className="text-red-600">Fehler: {error}</p>}
+          {data && (
+            <div className="space-y-2">
+              <div className="font-semibold text-slate-800">
+                {data.license_label_de ?? 'Lizenz unbekannt'}
+              </div>
+              {data.regulation_name_de && (
+                <div>
+                  <span className="text-slate-500">Quelle:</span>{' '}
+                  <span className="text-slate-800">{data.regulation_name_de}</span>
+                </div>
+              )}
+              {data.license_type && (
+                <div>
+                  <span className="text-slate-500">Lizenztyp:</span>{' '}
+                  <span className="text-slate-700">{data.license_type}</span>
+                </div>
+              )}
+              {data.attribution && (
+                <div className="rounded bg-amber-50 border border-amber-200 px-2 py-1.5">
+                  <div className="text-[10px] font-semibold text-amber-800 uppercase tracking-wide">
+                    Attribution-Pflicht
+                  </div>
+                  <div className="text-amber-900">{data.attribution}</div>
+                </div>
+              )}
+              {!data.render_full_text && (
+                <div className="text-[10px] text-slate-500 italic">
+                  Volltext wird im Output nicht gerendert — nur Identifier-Verweis.
+                </div>
+              )}
+              {data.source_url && (
+                <a
+                  href={data.source_url}
+                  target="_blank"
+                  rel="noopener noreferrer"
+                  className="inline-block text-[10px] text-blue-600 hover:underline mt-1"
+                >
+                  Originalquelle öffnen ↗
+                </a>
+              )}
+            </div>
+          )}
+        </div>
+      )}
+    </span>
+  )
+}
+
+export default SourceBadge