feat(dashboard): display secrets detection in logs table (#30)

feat(dashboard): display secrets detection in logs table (#30)

Add Secrets column to the Recent Requests table showing detected
secret types (e.g., OPENSSH_PRIVATE_KEY, PEM_PRIVATE_KEY) as red
badges. The data was already available from the API but not displayed.

- Add Secrets column header between PII Entities and Scan Time
- Parse secrets_types and secrets_detected from API response
- Display secret types as error-colored badges
- Add CSS utilities for error color variants
- Update colspan values for detail rows

Closes #20