Fix flicker on first chat input change

## Bug
On the first change to the chat input, the chat window flickers or appears to re-render for about one second. The issue does not recur on subsequent input changes.

## Steps to reproduce
1. Open the chat window.
2. Change the chat input for the first time.
3. Observe the chat window.

## Actual behavior
The chat window flickers or re-renders for approximately one second on the first input change.

## Expected behavior
Changing the chat input should not visibly flicker or cause an unnecessary full-window re-render, including on the first change.

## Acceptance criteria
- No visible flicker occurs on the first chat input change.
- Subsequent input changes continue to behave normally.

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Requested by **Ishaan** during a Conclave meeting.

Reproduce the issue by opening the chat window and changing the input for the first time, then locate the chat input and window components in the TypeScript client. Trace what differs on the first change and verify that the initial change no longer causes visible flicker or a full-window re-render while later changes remain normal.

Written by the indexing model from the issue text.