docs: add demo gif/video to README for better visual explainer

[NiveditJain]

Problem

The README currently lacks a visual demonstration of the project, making it harder for new users to quickly understand what the tool does and how it works.

Proposed Solution

Add a short GIF or screen-recorded video to the README that demonstrates:

• Installing and running failproof
• A sample workflow (e.g. triggering a post-publish smoke test)
• The dashboard in action

Why

• A visual demo reduces friction for first-time visitors
• GIFs/videos are the single most effective way to communicate CLI tool behavior at a glance
• Lowers the bar for contributors and early adopters to "get it" without reading everything

Acceptance Criteria

• Record a short demo (GIF via vhs/terminalizer, or MP4 via Loom/asciinema)
• Embed it near the top of the README, just below the intro paragraph
• Ensure it renders correctly on GitHub (GIF preferred for inline autoplay; video link as fallback)

[NiveditJain]

Closing as already shipped — the demo GIF was added to the README in PR #178 ([readme] add demo GIF, merged 2026-04-25). Reopen if there's something further you wanted here (compressed/LFS-hosted version, embedded video, etc.).