v0.21.0 - Fix Placeholder Timestamps in Templates and Examples

Changed

• README now flags the Architecture Decision Record (ADR) artifact type
  as deprecated in favor of Decision (DEC).

Fixed

• Replaced round, all-zero-time-of-day placeholder timestamps (frontmatter
  created/updated, and feat's body-level #### {timestamp} headings)
  across all 24 affected domain template/example files with realistic,
  non-round values, so they no longer invite copy-paste-without-substitution
  (GitHub issue #67).