* initial commit
* feat: implement deriveSessionTotalTokens function and update usage tests
* Added deriveSessionTotalTokens function to calculate total tokens based on usage and context tokens.
* Updated usage tests to include cases for derived session total tokens.
* Refactored session usage calculations in multiple files to utilize the new function for improved accuracy.
* fix: restore overflow truncation fallback + changelog/test hardening (#11551) (thanks @tyler6204)
- Add per-message dedup tracking in subscribeEmbeddedPiSession
- Compare both trimmed and normalized text to catch near-duplicates
- Reset dedup state on each new assistant message
- Add test for trailing whitespace edge case
Fixes duplicate Slack message delivery when the same text appears
with minor whitespace differences (e.g., trailing newline).
