Fix blocking busy-wait in typing handler using FIFO async queue

[Agarwalchetan]

Fix blocking busy-wait in typing handler using FIFO async queue

Acceptance Criteria fulfillment

• Removed synchronous busy-wait loop that could block the JavaScript event loop
• Implemented a FIFO async queue using Promise chaining to process typing events sequentially
• Preserved existing typing indicator behavior and event ordering
• Ensured robustness by preventing queue breakage if a typing callback throws
• Kept production logs clean by removing unsafe console.error calls
• Added unit tests validating sequential execution and final typing state

Fixes #1113

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Overview

This PR removes a critical performance bug where a synchronous while loop was used to lock the thread while handling typing events.
Because JavaScript is single-threaded, this could block the event loop and cause the host application or browser to freeze when multiple typing events occurred in quick succession.

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Changes

File:
packages/api/src/EmbeddedChatApi.ts

Fix:

• Replaced while (typingHandlerLock) {} with a FIFO async queue implemented via Promise chaining (this.typingChain)

Robustness:

• Added a try / catch block inside the queue consumer to ensure the queue remains functional even if a typing callback throws
• Removed unsafe console.error calls to avoid noisy production logs while preserving internal state consistency

Tests:

• Added unit tests verifying sequential processing of typing events and correctness of intermediate and final typing states

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Video / Screenshots

N/A (internal logic change; no UI modifications)

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PR Test Details

• Unit tests added for the typing handler logic
• Manual verification performed by simulating rapid typing events
• No public API changes

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This change replaces a blocking lock with an async FIFO queue to prevent UI freezes while preserving typing event ordering.

[CLAassistant]

All committers have signed the CLA.