Implement proper species sorting via label JOIN

[tphakala]

Background

Currently, species sorting uses label_id which is an auto-increment integer with no correlation to alphabetical species names. This provides stable grouping but not true alphabetical ordering.

Current State

• Location: internal/datastore/v2/repository/filter_conversion.go:559
• species_asc sort uses label_id ordering
• True alphabetical sorting requires joining with the labels table

Proposed Solution

1. Modify the detection query to JOIN with labels table when species sorting is requested
2. Order by labels.scientific_name instead of label_id
3. Consider performance implications (index on scientific_name may be needed)

Example Query Pattern

SELECT d.* FROM detections d
JOIN labels l ON d.label_id = l.id
WHERE ...
ORDER BY l.scientific_name ASC

Acceptance Criteria

• Species sorting uses actual species names (scientific_name)
• Performance is acceptable with index support
• Both ascending and descending order work correctly
• Tests for species sorting