Merge branch 'master' into worktree-mosaic-library

Renumbers the mosaic's requirement IDs out of the way of the download work
that landed on master in parallel: it had already claimed DR-163/DR-164 and
UT-162, so the mosaic layout is now DR-172, the library favourites scope
DR-173, and its composition test UT-167.

Note for the download branch: its UT-162..UT-165 rows trace to DR-163..DR-166,
none of which are defined in requirements.md — that branch defined DR-167..171
instead. Those references are orphaned and want a look; nothing here touches
them.

src/lib/utils/favoritesView.ts

@@ -41,7 +41,7 @@ export function resolveFavoritesScope(raw: string | null | undefined): Favorites
  * than folded into "all": a caller asking "which category is this?" wants no
  * answer, not the cross-category one.
  *
- * TRACES: UR-075 | DR-164
+ * TRACES: UR-075 | DR-173
  */
 export function asFavoritesScope(
   scope: SearchScope | null | undefined,