fix(skill): remove Charcoal from daytime compositions

Corner Warmth (daytime) no longer uses Charcoal. The lower-left anchor
is now a Keppel (#00B39F) blob, keeping the bottom of daytime images
in the teal/green family throughout.

Signed-off-by: Lee Calcote <lee.calcote@layer5.io>

Author: leecalcote