- prices.fetchPrice wraps invoke('fetch_price', ...) with local rate-limit (1/2s), in-flight dedup, exp backoff on 5xx (2/4/8s, max 3 retries), no retry on 4xx/429, hard 100/session cap
- 9 vitest tests with vi.useFakeTimers() (happy, 401/403/404, 429 no-retry, 5xx retries, dedup, pacing, session cap)
- Annexe B i18n mapping wired (PriceError → balance.priceFetching.errors.* keys)
- Session cap checked before rate-limit/dedup; failures do not consume budget (MEDIUM decision)
Closes#156
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
