Fix panic safety and deduplicate cleanup in StartDockerImageDownload goroutine

[Copilot]

Bug Fix

What was the bug?

The background goroutine in StartDockerImageDownload had no panic recovery — any unhandled panic would crash the entire process. Compounding this, the pullState.downloading[image] cleanup was open-coded on every return path (four copies), meaning a panic would also leave the flag set permanently, silently no-op-ing all future download attempts for that image until process restart.

Every sibling goroutine in the package (update_check.go, compile_update_check.go) already uses defer recover() with logging; this goroutine was the odd one out.

How did you fix it?

Replaced the four duplicate lock → delete → unlock blocks with a single defer that performs cleanup unconditionally and recovers from panics:

go func() {
    defer func() {
        pullState.mu.Lock()
        delete(pullState.downloading, image)
        pullState.mu.Unlock()
        if r := recover(); r != nil {
            dockerImagesLog.Printf("Panic in docker image download for %s (recovered): %v", image, r)
        }
    }()
    // retry loop — all four early returns now just `return`
}()

No semantic change on success or cancellation paths; panic path now recovers instead of crashing.

[Copilot]

Pull request overview

This PR improves the robustness of StartDockerImageDownload by ensuring the background download goroutine always cleans up its pullState.downloading flag and won’t crash the process if it panics.

Changes:

• Added a deferred cleanup in the download goroutine to always remove the image from pullState.downloading.
• Added recover() handling to log and recover from panics inside the goroutine.
• Removed duplicated cleanup blocks across multiple return paths.

Show a summary per file

File	Description
pkg/cli/docker_images.go	Adds deferred cleanup + panic recovery to the docker image pull goroutine and removes duplicated map cleanup code.

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• Files reviewed: 1/1 changed files
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