feat: add redacted sample clipboard export

[ded-furby]

Summary

Add a review-toolbar action that copies the currently selected redaction preset to the clipboard as tab-separated text for safer issue reports and discussions.

Motivation / linked issue

Closes #6.

Changes

• add copyRedactedSample so clipboard export reuses the existing masking rules for names and sensitive values
• add a Copy redacted sample review action plus localized status/hint copy in the UI
• extend browser QA to verify the button exists and that the copied sample masks the seeded settlement name
• document that issue reports should use synthetic fixtures or the redacted sample copy action

Testing

• npm run verify
• npm run qa:browser

Checklist

• Tests pass locally (pytest and/or viewer checks as applicable).
• Docs updated if behavior or public API changed.
• No secrets, credentials, or customer data committed.
• No breaking change, or a CHANGELOG.md entry is included.