Chat and engine connections retry and recover on their own

Transient connection failures in desktop chat and in the engine tool connection now retry in the background instead of surfacing raw errors. Release builds also check that their default packages exist before shipping.

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Engine tool connection keeps recovering

While a session stays open, the app keeps retrying the engine connection after temporary failures instead of giving up on it. If a tool-list refresh or a reconnect fails, the app recovers the tool list by itself without waiting for another notification from the engine, and the previous list stays usable in the meantime. This helps sessions survive an editor disconnecting during Play Mode changes or compilation. (#792)

Fixed

Chat recovers short connection failures

Brief certificate, DNS and connection failures no longer dump raw SDK error text into the chat. The app retries twice with a short backoff, and only if those attempts also fail does it show one friendly connection message. Recovery resumes the interrupted turn without resending earlier prompts, and any queued text that was never sent returns to the composer. (#789)

Release check for unpublished default packages

Starting a release now verifies that every default package version is actually published, and stops with a list of the missing ones if any are not. This keeps a build from shipping with default packages that cannot be resolved when a user installs it. (#790)

No image approval errors from unloaded panes

Restored or peeked transcript panes that have no live session no longer produce repeated image approval errors. They now simply report that no requests are pending, while real approval decisions and other windows keep the same refusals as before. (#791)