- Load custom field definitions and values in ViewIssue handler
- New sidebar template displays dropdown fields with onchange submit
- POST handler at /issues/{id}/custom-fields/{field_id} saves values
- Dropdown options parsed from JSON and passed to template
- Non-dropdown fields display as read-only text
- Section appears between Labels and Milestone in sidebar
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>