feat: update gateway pool and usage flows

frontend/src/features/usage/utils/__tests__/poolTrace.spec.ts

@@ -24,7 +24,7 @@ function buildCandidate(
 }
 
 describe('poolTrace', () => {
-  it('keeps only pool nodes that actually participated in scheduling audit fallback', () => {
+  it('keeps pool audit nodes even when they were not attempted', () => {
     const attempts = buildPoolAttemptCandidatesFromAudit([], [
       {
         candidate_index: 0,
@@ -68,11 +68,13 @@ describe('poolTrace', () => {
       },
     ], 'req-1')
 
-    expect(attempts).toHaveLength(2)
+    expect(attempts).toHaveLength(3)
     expect(attempts[0].key_id).toBe('key-success')
     expect(attempts[0].status).toBe('success')
     expect(attempts[1].key_id).toBe('key-skipped')
     expect(attempts[1].status).toBe('skipped')
+    expect(attempts[2].key_id).toBe('key-available')
+    expect(attempts[2].status).toBe('available')
   })
 
   it('preserves real trace attempts even when audit status is non-standard', () => {

frontend/src/features/usage/utils/poolTrace.ts

@@ -12,11 +12,6 @@ export const TIMELINE_STATUS: CandidateRecord['status'][] = [
   'stream_interrupted',
 ]
 
-const POOL_HIDDEN_STATUS = new Set<CandidateRecord['status']>([
-  'available',
-  'unused',
-])
-
 const PROVIDER_TYPE_LIKE_NAMES = new Set<string>([
   'codex',
   'kiro',
@@ -40,9 +35,7 @@ export const makeAttemptKey = (candidateIndex: number, retryIndex: number): stri
 }
 
 export const isPoolParticipatedCandidate = (candidate: CandidateRecord): boolean => {
-  if (POOL_HIDDEN_STATUS.has(candidate.status)) return false
-  if (candidate.status === 'pending' && !candidate.started_at) return false
-  return true
+  return TIMELINE_STATUS.includes(candidate.status)
 }
 
 export const isAttemptedCandidate = (