feat(protocol): add top-level status field to EofPayload

Add RunStatus directly on EofPayload so clients can read the terminal
run status without drilling into run_progress.derived.status.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Committed-By-Agent: claude

Author: tonyxiao

apps/engine/src/__generated__/openapi.json

@@ -548,11 +548,13 @@ export async function createEngine(resolver: ConnectorResolver): Promise<Engine>
             // takeLimits appends a minimal eof signal ({ type: 'eof', eof: { has_more } })
             if (raw.type === 'eof') {
               const hasMore = (raw as { eof: { has_more: boolean } }).eof.has_more
+              const runProgress = syncState.sync_run.progress
               yield emit(
                 engineMsg.eof({
+                  status: runProgress.derived.status,
                   has_more: hasMore,
                   ending_state: syncState,
-                  run_progress: syncState.sync_run.progress,
+                  run_progress: runProgress,
                   request_progress: requestProgress,
                 })
               )

apps/engine/src/lib/engine.ts

@@ -416,6 +416,7 @@ export type SyncState = z.infer<typeof SyncState>
 
 export const EofPayload = z
   .object({
+    status: RunStatus.describe('Terminal run status derived from stream outcomes.'),
     has_more: z
       .boolean()
       .describe(