fix(core,cli): attribute figma REST failures to the endpoint that failed

cli_error had no way to tell which figma REST call (images, files_nodes,
variables_local, styles, ...) actually hit RATE_LIMITED/FORBIDDEN/etc, so
the dashboard could see failures spike but not which call caused them.

FigmaClientError now carries a low-cardinality endpoint label (never the
raw fileKey/nodeId), threaded through to cli_error's endpoint property.

packages/cli/src/commands/figma/cliError.ts

@@ -29,6 +29,7 @@ export async function withFigmaErrors(command: string, fn: () => Promise<void>):
           stack_trace: err.stack,
           command,
           kind: "command_error",
+          endpoint: err instanceof FigmaClientError ? err.endpoint : undefined,
         });
         await telemetry.flush();
       } catch {