fix(tui): handle timeout/error subagent statuses in /agents (#26687)

Accept delegation timeout/error statuses in the TUI subagent model, normalize unknown status strings defensively, and harden /agents overlay rendering/sorting so unknown statuses cannot crash glyph/color lookup. Add regression tests for live event normalization and disk snapshot replay.

ui-tui/src/app/spawnHistoryStore.ts

@@ -1,7 +1,7 @@
 import { atom } from 'nanostores'
 
 import type { SpawnTreeLoadResponse } from '../gatewayTypes.js'
-import type { SubagentProgress } from '../types.js'
+import type { SubagentProgress, SubagentStatus } from '../types.js'
 
 export interface SpawnSnapshot {
   finishedAt: number
@@ -21,6 +21,26 @@ export interface SpawnDiffPair {
 
 const HISTORY_LIMIT = 10
 
+const KNOWN_SUBAGENT_STATUSES = new Set<SubagentStatus>([
+  'completed',
+  'error',
+  'failed',
+  'interrupted',
+  'queued',
+  'running',
+  'timeout'
+])
+
+const normalizeSubagentStatus = (status: unknown, fallback: SubagentStatus): SubagentStatus => {
+  if (typeof status !== 'string') {
+    return fallback
+  }
+
+  const normalized = status.toLowerCase() as SubagentStatus
+
+  return KNOWN_SUBAGENT_STATUSES.has(normalized) ? normalized : fallback
+}
+
 export const $spawnHistory = atom<SpawnSnapshot[]>([])
 export const $spawnDiff = atom<null | SpawnDiffPair>(null)
 
@@ -128,7 +148,7 @@ function normaliseSubagent(raw: unknown): SubagentProgress {
     parentId: s(o.parentId) ?? null,
     reasoningTokens: n(o.reasoningTokens),
     startedAt: n(o.startedAt),
-    status: (s(o.status) as SubagentProgress['status']) ?? 'completed',
+    status: normalizeSubagentStatus(o.status, 'completed'),
     summary: s(o.summary),
     taskCount: typeof o.taskCount === 'number' ? o.taskCount : 1,
     thinking: (arr<string>(o.thinking) ?? []).filter(x => typeof x === 'string'),