Add Case insensitive search

[mcgong720]

Description

Add a case-insensitive search toggle to the keyword search sidebar that works across all three query engines (Gremlin, OpenCypher, SPARQL).

• Gremlin: Uses regex() with (?i) flag for case-insensitive matching. Escapes the $ regex anchor as \$ to prevent Groovy string interpolation errors. Regex metacharacters in search terms are escaped to avoid injection.
• OpenCypher: Wraps attribute values and search terms in toLower() for case-insensitive comparison on both partial and exact matches.
• SPARQL: Uses regex() with "i" flag for partial matches and lcase() for exact matches.

The toggle does not apply to ID-based searches since IDs are system-generated and case-sensitivity is not meaningful.

Validation

• Unit tests: 17 new tests added for case-insensitive search:
  • Gremlin (keywordSearchTemplate.test.ts - 6 new):
    • Case-insensitive partial match generates regex("(?i).*term.*") syntax
    • Case-insensitive exact match generates regex("(?i)^term\$") with escaped $ to prevent Groovy interpolation
    • Case-insensitive is not applied to ID-based searches (IDs use standard containing() or exact match)
    • Case-sensitive mode (toggle off) still uses standard containing() and exact string match
    • Regex metacharacters in search terms (e.g., test.com) are escaped as test\\.com in partial match
    • Regex metacharacters are escaped in exact match too (test\\.com\$)
  • OpenCypher (keywordSearchTemplate.test.ts - 5 new):
    • Case-insensitive partial match wraps both sides in toLower(): toLower(toString(v.attr)) CONTAINS toLower("term")
    • Case-insensitive exact match uses toLower(toString(v.attr)) = toLower("term")
    • Case-insensitive is not applied to ID searches (IDs use toString(id(v)) without toLower)
    • Case-sensitive mode (toggle off) uses plain v.attr CONTAINS "term" without toLower()
    • Combined test with multiple vertex types, multiple attributes, ALL_ATTRIBUTES token, limit, and offset
  • SPARQL (keywordSearchTemplate.test.ts - 3 new):
    • Case-insensitive partial match uses regex(str(?value), "term", "i") with the "i" flag
    • Case-insensitive exact match uses lcase(str(?value)) = lcase("term") for string comparison
    • Partial match remains case-insensitive even when caseInsensitive flag is false (SPARQL's contains() is inherently case-sensitive, so partial match always uses regex with "i")
  • Search Sidebar (useKeywordSearch.test.ts - 3 new):
    • caseInsensitive defaults to false for Gremlin connections
    • caseInsensitive defaults to false for OpenCypher connections
    • caseInsensitive defaults to false for SPARQL connections
• Manual testing with Gremlin Server (air_routes sample data): Verified partial and exact match with case-insensitive toggle on/off.
• Manual testing with JanusGraph: Loaded mixed-case test data (JFK, lax, ORD, san francisco). Verified case-insensitive search works.
• Manual testing with BlazeGraph (SPARQL): Loaded RDF triples with mixed-case data. Verified regex("i") flag works for partial matches and lcase() works for exact matches.
• Manual testing with Neptune: Tested all three query languages (Gremlin, OpenCypher, SPARQL). Case-insensitive search works correctly for both partial and exact matches.

Related Issues

• Addresses [Feature request] Attribute search should be case-insensitive #89

Check List

• I confirm that my contribution is made under the terms of the Apache 2.0 license.
• I have run pnpm checks to ensure code compiles and meets standards.
• I have run pnpm test to check if all tests are passing.
• I have covered new added functionality with unit tests if necessary.
• I have added an entry in the Changelog.md.

[kmcginnes]

@mcgong720 Excellent. I just took a quick glance and I like it.

I have a few other things to attend to before reviewing this. So it might be a few days before I can take a closer look.