fix(api): regenerate client for RB-08's 403 response shape

RB-08 changed DELETE /admin/uploads/{documentId}'s 403 mapping from
.Produces to .ProducesProblem, matching CasesAdmin's actual
Results.Problem() response - but the generated OpenAPI doc and typed
client were never regenerated alongside it, so CI's api-client-drift
check (npm run gen:api && git diff --exit-code) was left red. No
frontend consumes this admin-only endpoint (confirmed by grep), so
this is a pure regeneration with no consumer impact.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

backend/swagger.json

@@ -400,7 +400,14 @@
             "description": "No Content"
           },
           "403": {
-            "description": "Forbidden"
+            "description": "Forbidden",
+            "content": {
+              "application/problem+json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ProblemDetails"
+                }
+              }
+            }
           },
           "404": {
             "description": "Not Found"

libs/shared/src/infrastructure/api-client.ts

@@ -612,7 +612,9 @@ export class ApiClient {
             });
         } else if (status === 403) {
             return response.text().then((_responseText) => {
-            return throwException("Forbidden", status, _responseText, _headers);
+            let result403: any = null;
+            result403 = _responseText === "" ? null : JSON.parse(_responseText, this.jsonParseReviver) as ProblemDetails;
+            return throwException("Forbidden", status, _responseText, _headers, result403);
             });
         } else if (status === 404) {
             return response.text().then((_responseText) => {