docs: add animated Looper header and simplify README - #7

Summary

• Add a dark, profile-style animated SVG illustrating the work cycle and 20-attempt limit, with descriptive alternative text and reduced-motion support.
• Use plain-language explanations throughout the README while preserving runnable commands and safety rules.
• Match the README introduction, skill description, and live repository About text exactly.

Validation

• Checked SVG XML, local README links, unchanged runnable examples, exact description matching, and git diff --check.
• Rendered and visually inspected the full header in Chrome.