Send 1st message faster for app generation

[pffigueiredo]

As of right now, when we start the app generation process, the time between the user sending the request and the agent responding seems to be around 30s.

However, the agent is quite fast to generate an initial planning of what it is about to do, but that message it not sent right away, making the UX for consumers seems kinda slow.

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If possible, it would be nice for the Agent to respond with some sort of planning right away, so that the experience looks faster.

Slack Thread: https://neondb.slack.com/archives/C087Q9EM7S9/p1750237385787519