Capture researcher identity on reports

[tikket1]

Context

We don't store who submitted each report. The H1 API returns reporter info in relationships.reporter.data.

Missing Fields

• reporter_username — H1 username of the researcher
• reporter_external_id — H1 user ID
• reporter_reputation — reputation score at time of report (if available)
• reporter_profile_picture_url — avatar

Changes Needed

1. Add reporter_username, reporter_external_id columns to Report model
2. Extract from relationships.reporter.data in adapter
3. Add to ReportData dataclass and schemas
4. Display on report detail page

Value

Essential for multi-user setups or tracking your own submissions across platforms. Also useful for correlating researcher activity.