- Migrated 288 lines of scattered error classification logic from `utils/error-id.ts` into a cohesive `packages/ai/src/error/` module with 13 specialized submodules covering flags, classes, OAuth, providers, rate-limiting, and finalization.
- Replaced 100+ generic `Error` throws across 60+ provider and registry files with semantic `AIError.*` classes (e.g., `AIError.MissingApiKeyError`, `AIError.OAuthError`, `AIError.ProviderResponseError`), improving error diagnostics and retry logic.
- Consolidated error utility imports from `pi-utils` and scattered classification functions into a single `AIError` namespace, reducing coupling and simplifying error handling across all packages.
- Improved thinking loop detection logic by refining text normalization and treating stalls as retryable errors.
- Instrumented the agent session to recognize thinking loop markers within retryable error conditions.
- Automated the clearing of stale error banners upon successful auto-retry execution.
- Added comprehensive test coverage for chunked thinking loop errors and banner management.
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