Add boolean field filtering support

[kueda]

Summary

This PR adds support for filtering records by boolean fields in the database search functionality. Boolean columns can now be filtered using a dropdown selector in the UI that allows users to select "true", "false", or "Any" (no filter).

Key Changes

• Backend (Rust): Added boolean field filtering logic in the database search query builder that directly compares boolean columns to TRUE/FALSE values, with case-insensitive string matching for filter input
• Frontend (Svelte): Implemented a dropdown filter component for boolean columns that appears in the filter panel alongside existing filter types
• Type definitions: Added 9 boolean field definitions to SearchParams interface and exported a BOOLEAN_COLUMNS constant for identifying which columns should use boolean filtering
• Tests: Added two comprehensive test cases validating filtering by boolean fields for both true and false values

Implementation Details

• Boolean filter values are matched case-insensitively ("true"/"false" strings) and invalid values are silently skipped
• The UI dropdown provides three options: "Any" (clears filter), "true", and "false"
• Boolean columns include: captive, hasCoordinate, hasGeospatialIssues, hasTaxonomicIssue, hasNonTaxonomicIssue, identificationCurrent, isInvasive, isSequenced, and repatriated

https://claude.ai/code/session_01PxRHnUPkPJB8mGTgjbeMgq