Challenge 3: Propagation Scope — Single File vs. Shared Library — Solution Walkthrough

The answer:

Per this chapter's own material, a color style update and a component
update both "propagate" in the same underlying sense as Chapter 5's own
main component/instance relationship: a single edit made in one shared
place automatically updates every element that references it, without
needing to individually track down and update each usage.

Why the scope is genuinely different in a shared library:

Chapter 5 described propagation confined to a single file — a main
component's instances only exist, and only get updated, within that
one file. A published library extends that exact same propagation
mechanism across every file that has access to the library, not just
one — updating and republishing a library component or style ripples
out to every file using that library, potentially dozens of separate
files at once.

Why this is the same mechanism at a larger scale, not a different one:

The underlying idea — one shared source, many linked copies, a single
edit propagating outward — is identical in both cases. The only real
difference this chapter identifies is how far that propagation reaches:
one file's own instances, versus every file across an entire team that
draws from the same published library.

WHY THIS WORKS AS AN ANSWER
------------------------------
This exercise checks that library-level propagation is correctly
recognized as the same underlying mechanism as Chapter 5's own
component propagation, scaled up from a single file to an entire
team's worth of files.