Applies the new write_readme companion-doc convention to ai-stack,
paintplus, and kyber-launcher: install-time-invariant content (usage
walkthroughs, service tables, troubleshooting) moves out of the .sh
heredocs into sibling services/<name>.md files, leaving only genuinely
install-specific content inline.
- services/paintplus.md: config/cloud/GPU/ai-stack-backend/update/Caddy
sections, picked up automatically via write_readme's companion-doc
support.
- services/ai-stack.md: roles, GPU switcher, service URLs, cloud LLM
provider setup, update, Caddy. ai-stack.sh can't use write_readme
directly (its POST-INSTALL-NOTES.md filename deliberately avoids
colliding with the vendored app's own README.md in the same
directory), so it appends the companion file manually.
- services/kyber-launcher.md: the full SWBF2 (2017) + Kyber walkthrough,
moved out of the root README's "Gaming scripts" section (which now
just points here). kyber-launcher.sh now calls write_readme to deploy
it to ~/.local/share/kyber/README.md, fixing a stale in-script pointer
to a README section that no longer exists.
