docs: show Sopify in a real Codex workflow

[Li-Sanze]

Summary

• Replace the simulated Claude-to-Codex terminal demo with a validated animation based on an archived real Codex workflow.
• Explain Sopify from the user perspective: plan first, stop for a decision, and close with evidence.
• Keep the maintainable JSON/SVG sources with the GIF and remove the obsolete demo asset.

Evidence boundary

The animation reconstructs the flow. The README links the archived plan, verification receipt, and final receipt as the behavioral evidence.

Validation

• README structure and relative-link validation passed; body line counts remain 158 / 155.
• Focused README/plain-language tests: 20 passed.
• Fireworks JSON/SVG validation: XML, markers, geometry, and composition passed.
• GIF: 960x700, 5.75s, 20fps, 115 frames, 183963 bytes; motion report and FFprobe passed.
• Independent Cursor review accepted the final seven-file scope and bilingual framing.

Scope

Documentation-only change. No Sopify plan package, PNG review artifact, GitHub Pages change, installer/runtime behavior, version bump, tag, or Release.