Add public remembrance form guidance

[megabyte0x]

Summary

• adds a short implementation note for choosing the right public remembrance form after the first obituary-writing draft
• distinguishes private reflection, family life story, reported article, eulogy, and short death notice uses
• cites FinalNotes obituary story and obituary article guides as practical checkpoints for choosing the form

Checks

• Parsed the pattern frontmatter locally with Ruby/Psych after the edit.