docs(#34): document ticket template YAML frontmatter format

[imtushar01]

Description

Adds documentation for the YAML frontmatter format required for all tickets in the CHT-Agent project.
This improves clarity and provides a structured reference for contributors creating new tickets.

#34

[sugat009]

Thanks for the updates, this looks good overall. One more thing before we merge:
The agent-memory/TEMPLATE.md still uses enhancement and refactoring as category values (lines 12, 65, 81, 259), and there's one context file (agent-memory/domains/forms-and-reports/issues/8336-support-trigger-column.md) that uses category: enhancement.
Since this PR renames enhancement → improvement across the codebase, could you update these too for consistency?

• agent-memory/TEMPLATE.md — replace both enhancement and refactoring with
  improvement in the category enum, examples, and description. The valid
  categories should be bug, feature, improvement.
• agent-memory/domains/forms-and-reports/issues/8336-support-trigger-column.md
  — change category: enhancement to category: improvement

[imtushar01]

Thanks for pointing that out! I’ve updated all remaining instances.
Everything should now align with the updated category values (bug, feature, improvement). Let me know if anything else needs tweaking