feat(images): add Docker Hub image search and pull

[ronakmaheshwari]

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PR Title

feat(images): add Docker Hub image search and pull

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PR Description

What

Adds a Docker Hub search feature to the Images panel. Press p to open a search prompt, browse results, and pull an image — all without leaving lazydocker.

How to use

1. Navigate to the Images panel (4)
2. Press p — a "Search Docker Hub:" prompt appears
3. Type a query (e.g. alpine, postgres) and press Enter
4. A scrollable results menu shows up to 25 matches with:
   • Image name (official images marked with [Official])
   • Short description
   • Star count and Pull count
5. Navigate with j/k, press Enter to run docker pull <image>
6. Press Esc to dismiss

Changes

File
pkg/commands/dockerhub.go	New — HTTP client for the Docker Hub public search API (hub.docker.com/v2/search/repositories)
pkg/gui/dockerhub_panel.go	New — prompt handler, async search with loading status, results menu, pull subprocess
pkg/i18n/english.go	Added translation strings for the new feature
pkg/gui/keybindings.go	Added p keybinding on the images view

Notes

• Uses the public Docker Hub API — no authentication required
• No new external dependencies — only stdlib net/http and encoding/json
• Pulls the image as a subprocess so live docker pull output is visible in the terminal
• All existing tests pass

Screenshots

[ronakmaheshwari]

@pvande @tylerstillwater @camflan Can you please review it