fix(desktop): first message in new chat not sent — stays in input field

[gauravsaxena1997]

Fixes #63574. The first message in a new chat on Windows sometimes stays in the input field when Enter or Send is pressed, requiring a second press to actually send. This PR addresses the underlying state synchronization issue in the chat composer.

[teknium1]

Thanks for reporting the new-chat first-send failure. This is already fixed on current main by an automated hermes-sweeper review.

• Commit 8c288760d0b50107e608ed42df81f48c7ccedde5 (fix(desktop): stop the submit drift guard from aborting every new chat) handles the legitimate session/route re-home during new-chat creation.
• apps/desktop/src/app/session/hooks/use-prompt-actions/submit.ts:559 verifies the created session remains active, re-pins the submit context, and continues the send.
• apps/desktop/src/app/session/hooks/use-prompt-actions/index.test.tsx:3472 regression-tests submission of the first prompt in a brand-new chat.
• This PR's diff contains no Desktop composer or session-submit changes, so it does not add to the resolved report.