Themes Package System

See also themes/README.md in the product repo. Built-ins Streamly / Streamlix / StreamTube are all Final.

Layout

themes/<id>/
  theme.json
  config.ts
  skin.ts
  index.ts
  *Template.tsx

Method	Path	Effect
`GET`	`/api/operator/themes`	List (no config writes)
`POST`	`/api/operator/themes/apply`	Apply + presets; never overwrite SEO
`GET`	`/api/operator/themes/[themeId]/export`	`.streamly-theme.zip`
`DELETE`	`/api/operator/themes/[themeId]`	Soft-uninstall uploaded
`POST`	`/api/operator/themes/install`	Zip install (does not Apply)

Gallery zip IO UI hidden (SHOW_THEME_PACKAGE_IO_UI = false).

theme.json + config.json only — cannot ship new React templates; must use built-in templateEntry.

/?__theme_preview=<themeId> — admin only; in-memory; flips data-storefront-theme.