fix(ai-gateway): extend generation polling timeout

[chrarnoldus]

Summary

• configure fetchGeneration to use the existing backoff helper with a five-minute maximum retry budget
• start retries at five-second intervals so generation polling remains gentle; the existing exponential backoff yields roughly nine attempts over about four minutes
• raise every transcription route alias that can reach generation usage processing to maxDuration = 1800
• add focused coverage for the generation backoff options and route duration exports

Verification

• pnpm --filter web exec jest --runInBand src/lib/ai-gateway/providers/upstream-request.generation.test.ts src/app/api/openrouter/audio/transcriptions/route.test.ts (6 tests passed)
• pnpm --filter web typecheck
• pnpm --filter web lint

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Executive Summary

The follow-up commit narrows the generation-polling change to a minimal fetchWithBackoff tuning (baseDelayMs/maxDelayMs), reverting the earlier attemptTimeoutMs/AbortSignal/maxBackoffDelayMs additions back to main's existing implementation, with tests updated to match; no new bugs, security issues, or logic errors were found in the changed lines.

Files Reviewed (2 changed files in this update)

• apps/web/src/lib/ai-gateway/providers/upstream-request.ts
• apps/web/src/lib/ai-gateway/providers/upstream-request.generation.test.ts

Previous Review Summary (commit 5ed4868)

Current summary above is authoritative. Previous snapshots are kept for context only.

Previous review (commit 5ed4868)

Status: No Issues Found | Recommendation: Merge

Executive Summary

Reviewed the generation-polling timeout/backoff rework and route maxDuration bumps with high confidence and found no security, correctness, or logic bugs in the changed lines.

Files Reviewed (9 files)

• apps/web/src/app/api/gateway/audio/transcriptions/route.ts
• apps/web/src/app/api/gateway/v1/audio/transcriptions/route.ts
• apps/web/src/app/api/openrouter/audio/transcriptions/route.test.ts
• apps/web/src/app/api/openrouter/audio/transcriptions/route.ts
• apps/web/src/app/api/openrouter/v1/audio/transcriptions/route.ts
• apps/web/src/lib/ai-gateway/providers/upstream-request.generation.test.ts
• apps/web/src/lib/ai-gateway/providers/upstream-request.ts
• apps/web/src/lib/fetchWithBackoff.test.ts
• apps/web/src/lib/fetchWithBackoff.ts

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_{Reviewed by claude-sonnet-5 · Input: 60 · Output: 16K · Cached: 2.6M}

_{Review guidance: REVIEW.md from base branch main}