docs: sync install steps across all languages

docs: clarify install + run steps

docs: sync all language READMEs with new layout

docs: polish README layout

docs: update demo SVG with rare capybara

docs: add animated SVG demo (hatching ceremony)

docs: remove demo GIF, use ASCII art

docs: better demo GIF — 886 frames, 30fps hatching animation

docs: add animated demo GIF to README

docs: add multi-language README (zh, ja, fr, ru)

docs: capitalize title

docs: fix ASCII art rendering on GitHub

docs: polish README with centered header, sections, cleaner layout

cleanup: remove stale files, fix all naming references

feat: add OpenCode one-liner installer