fix(v0.4.1): route all workspace commands through SearchRoots

Every resolver, lister, and most-recent caller now passes
config.SearchRoots() so CTASK_PROJECT_ROOT is searched alongside
CTASK_ROOT. Commands use ws.Root when rendering relative paths or
session env vars so displays and CTASK_ROOT exports are correct for
workspaces living under CTASK_PROJECT_ROOT.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

cmd/last.go

@@ -31,9 +31,9 @@ func init() {
 }
 
 func runLast(cmd *cobra.Command, args []string) error {
-	root := config.ResolveRoot()
+	roots := config.SearchRoots()
 
-	best, err := workspace.MostRecentActive(root)
+	best, err := workspace.MostRecentActive(roots)
 	if err != nil {
 		return err
 	}