Cookbook v0.17.1

Patch Changes

• #95 3f65be3 Thanks @tenphi! - Restore strong heading and body colors with absolute Glaze tones: body text
  starts at 0 and headings at 4, with normal-mode tone boundaries applied by Glaze.
  Expose the heading palette role and configurable Heading style tree. Update the packaged palette examples to preserve dark
  reading text, adapt it for dark and high-contrast modes, and use contrast
  requirements as minimum safeguards.