Join 11: gitea reads the step event's fingerprint by the seat's name

The seat mesh-pipeline-runner's step event carries `fingerprint`; gitea read
`fp`, which no event carries, and which the type-check refuses once the Node
fetch places the runner's contracts (design 47 G A-285).

Builds: design 47 G A-285

Claude-Session: https://claude.ai/code/session_01NcbgfGKaxw984XyAPfLm4h

modules/gitea/failedsteps.ts

@@ -89,7 +89,7 @@ export class FailedSteps {
 
   private record(ev: StepEndedEvent): Promise<void> {
     const r = ev?.result;
-    const fingerprint = r?.fingerprint || ev?.fp || "";
+    const fingerprint = r?.fingerprint || ev?.fingerprint || "";
     if (!r || !SHA.test(String(ev.commit ?? "")) || !fingerprint || !ev.module) return Promise.resolve();
     return this.turn(async () => {
       const at = ev.at ?? new Date().toISOString();