#8661: fix: display rate limit errors correctly instead of as context overflow

## Summary - Rate limit errors were being displayed as "Context overflow" to users - This was misleading since the actual error was a rate limit, not context size ## Root cause - In `formatAssistantErrorText`, the context overflow check happened before the rate limit check - Both error types can contain "request" keywords, causing false positives ## Changes - Added rate limit check before the context overflow check in error formatting - Users now see "Rate limit exceeded. Please wait a moment before trying again." ## Test plan - [x] Run type checking (`npm run check`) - [x] Run error helper tests (`vitest run src/agents/pi-embedded-helpers`) Fixes #8047 🤖 Generated with [Claude Code](https://claude.com/claude-code) <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This PR adjusts assistant error formatting so rate limit errors are detected and surfaced to users before the more general context overflow check, preventing rate-limit payloads that contain "request" wording from being mislabeled as context overflow. The change is localized to `src/agents/pi-embedded-helpers/errors.ts` in `formatAssistantErrorText`. One inconsistency remains: `sanitizeUserFacingText` still maps rate limit errors to the same message as overloaded errors, which may continue to misreport rate limits in any flow that uses that sanitizer rather than `formatAssistantErrorText`. <h3>Confidence Score: 4/5</h3> - This PR is likely safe to merge and fixes the reported misclassification in the primary formatter. - The change is a small reordering in `formatAssistantErrorText` and should not affect unrelated error cases. The main remaining concern is user-facing consistency: rate limit errors may still be mislabeled as overloaded in code paths using `sanitizeUserFacingText`, which could partially negate the intended UX fix depending on call sites. - src/agents/pi-embedded-helpers/errors.ts (sanitizeUserFacingText rate limit handling) <!-- greptile_other_comments_section --> <!-- /greptile_comment -->