feat: group proceeding types by jurisdiction in UI dropdowns

- DeadlineCalculator: use optgroup to group by UPC/DE
- DeadlineWizard: add section headers for each jurisdiction
- CaseForm: replace hardcoded TYPE_OPTIONS with API-fetched
  proceeding types grouped by jurisdiction
- Added 3 new DE proceeding types to DB: DE_PATENT,
  DE_NULLITY, DE_OPPOSITION

frontend/src/components/deadlines/DeadlineCalculator.tsx

@@ -85,11 +85,27 @@ export function DeadlineCalculator() {
               className={inputClass}
             >
               <option value="">Bitte wählen...</option>
-              {proceedingTypes?.map((pt) => (
-                <option key={pt.id} value={pt.code}>
-                  {pt.name} ({pt.code})
-                </option>
-              ))}
+              {(() => {
+                const grouped = new Map<string, ProceedingType[]>();
+                for (const pt of proceedingTypes ?? []) {
+                  const key = pt.jurisdiction ?? "Sonstige";
+                  if (!grouped.has(key)) grouped.set(key, []);
+                  grouped.get(key)!.push(pt);
+                }
+                const labels: Record<string, string> = {
+                  UPC: "UPC-Verfahren",
+                  DE: "Deutsche Patentverfahren",
+                };
+                return Array.from(grouped.entries()).map(([jurisdiction, types]) => (
+                  <optgroup key={jurisdiction} label={labels[jurisdiction] ?? jurisdiction}>
+                    {types.map((pt) => (
+                      <option key={pt.id} value={pt.code}>
+                        {pt.name} ({pt.code})
+                      </option>
+                    ))}
+                  </optgroup>
+                ));
+              })()}
             </select>
           </div>
           <div>