Real progress bars for pull, push, and build operations

[GustavoCaso]

Summary

Replace the generic spinner overlay with real per-layer progress bars during image pull, push, and (future) build operations, using the Docker API progress stream.

Current State

• Image pull and push show a static spinner with no progress info
• The Docker API returns a JSON stream of progress events ({"status","progressDetail","id",...}) that is not being parsed for the UI

Implementation Steps

1. Define a progress event model

type ProgressEvent struct {
    ID      string  // layer ID
    Status  string  // "Pulling fs layer", "Downloading", "Pull complete", etc.
    Current int64
    Total   int64
}

2. Parse the Docker progress stream

Create a helper internal/ui/progress/stream.go that reads io.ReadCloser from pull/push and emits ProgressEvent messages into the Bubble Tea runtime via tea.Cmd.

3. Build a progress panel component

Create internal/ui/components/progress/ with a Model that:

• Maintains a map of layer ID → progress state
• Renders a list of per-layer progress bars (using lipgloss or a simple ASCII bar)
• Shows overall completion status

4. Integrate with image pull

In the images section, when a pull starts:

• Launch the progress stream command
• Open the progress panel as an overlay
• Update the panel as ProgressEvent messages arrive
• Close and refresh image list on completion

5. Integrate with image push

Same pattern as pull.

Acceptance Criteria

• Pulling an image shows a per-layer progress bar
• Layer statuses update in real time (Pulling → Downloading → Pull complete)
• Overall completion is indicated
• The panel closes automatically on success
• Errors in the stream are surfaced as error banners
• Works with multi-platform pulls