Merge branch 'worktree-agent-a02f88e8490625846'

# Conflicts:
#	GerbilManagerWebAPI/ApplicationContext.cs
#	GerbilManagerWebAPI/Program.cs
#	gerbil-manager-web/e2e/mock-data.ts
#	gerbil-manager-web/src/App.tsx
#	gerbil-manager-web/src/components/AppShell.tsx
#	gerbil-manager-web/src/strings/de.ts

gerbil-manager-web/e2e/mock-api.ts

@@ -706,6 +706,42 @@ export async function installMockApi(page: Page): Promise<MockDb> {
       return json(route, 405)
     }
 
+    // RÜCKNAHMEN: zurückgenommene Tiere (CRUD /returns, GET optional ?gerbilId=).
+    // Eigene Route (kein Gridify-Paging — die API liefert ein flaches Array).
+    const ret = path.match(/^\/returns(?:\/([^/]+))?$/)
+    if (ret) {
+      const retId = ret[1] ? decodeURIComponent(ret[1]) : null
+      if (!retId) {
+        if (method === 'GET') {
+          const gid = url.searchParams.get('gerbilId')
+          const rows = gid ? db.returns.filter((r) => r.gerbilId === gid) : db.returns
+          return json(route, 200, [...rows].reverse())
+        }
+        if (method === 'POST') {
+          const body = request.postDataJSON() as Row
+          if (!body.gerbilId && !body.gerbilName) {
+            return json(route, 400, 'Es muss ein Tier angegeben werden.')
+          }
+          const created = { id: newId('return'), ...body, createdAt: new Date().toISOString() }
+          db.returns.push(created)
+          return json(route, 201, created)
+        }
+        return json(route, 405)
+      }
+      const idx = db.returns.findIndex((r) => r.id === retId)
+      if (method === 'PUT') {
+        if (idx < 0) return json(route, 404, { title: 'Not Found' })
+        Object.assign(db.returns[idx], request.postDataJSON() as Row)
+        return json(route, 200, db.returns[idx])
+      }
+      if (method === 'DELETE') {
+        if (idx < 0) return json(route, 404, { title: 'Not Found' })
+        db.returns.splice(idx, 1)
+        return json(route, 204)
+      }
+      return json(route, 405)
+    }
+
     // Generische Kollektionen: /<resource> und /<resource>/<id>
     m = path.match(/^\/([a-z-]+)(?:\/([^/]+))?$/)
     const col = m ? collections[m[1]] : undefined