Vertical-scroll strip mode moved from `fresco` to a standalone
`fresco_strip` package in fresco 0.6.0. Etcher's strip-renderer
detects strip handles at runtime via `"scrollTo" in handle`, so
the runtime side needs no code change — but the dep constraint
needs to accept both fresco 0.5.x (where strip lived in-package)
and fresco 0.6.0+ (where strip lives in `fresco_strip`).

  - mix.exs: {:fresco, "~> 0.5.9"} → {:fresco, "~> 0.5.9 or ~> 0.6.0"}

Consumers using strip mode pair this with `{:fresco_strip, "~> 0.1.0"}`
in their own mix.exs. Both packages contribute handles to the
same `window.Fresco.viewerRegistry` so Etcher finds them
uniformly regardless of source package.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>