Send button has no feedback; input appears to send slowly (char-by-char?)

[SGudbrandsson]

Problem

Pressing Send gives no visual feedback — the button doesn't indicate that the message is being sent. For longer inputs there is a noticeable delay, and it looks like the app may be sending the input one character at a time (streaming keystrokes) rather than delivering it as a single payload.

Expected

• Send button gives immediate feedback (pending/sending state, disabled, spinner, etc.) so I know the click registered.
• The full input is delivered to the backend in a single request; the backend is responsible for injecting it into the session at once, not char-by-char from the client.
• Progress/completion is visible so I'm not left wondering whether it worked.

Acceptance criteria

• Send button shows a pending state the moment it's pressed.
• Input is posted as a single payload (not streamed char-by-char from the frontend).
• Delay between click and confirmation is minimal.
• User sees a clear success/failure indication.