Add Gremlin Query Language Support

[rysweet]

Summary

Adds Apache TinkerPop Gremlin query language support alongside existing Cypher translation.

What's New

Gremlin Parser:

• Parses Gremlin method chains: g.V().hasLabel('User').out('OWNS').values('name')
• 48/49 tests passing
• Handles: g.V(), hasLabel(), has(), out/in/both(), values(), limit()

Translation Strategy:

• Gremlin → Gremlin AST → Cypher AST → KQL
• Reuses all existing Cypher-to-KQL infrastructure
• No duplication of translation logic

Integration:

• main_translator.py auto-detects language (queries starting with 'g.' are Gremlin)
• Same translator handles both Cypher and Gremlin
• 7/7 integration tests passing

Examples

g.V().hasLabel('User').has('age',30).out('OWNS').values('name')

Translates to:

IdentityInfo
| make-graph AccountObjectId with_node_id=AccountObjectId
| graph-match (v0:User)-[OWNS]->(v1)
| where v0.age == 30
| project v1.name

Testing

• Gremlin parser: 48/49 tests passing
• Integration: 7/7 tests passing
• All existing Cypher tests still passing

Files Changed

• New: src/yellowstone/gremlin/ (7 files, ~3,300 lines)
• Modified: src/yellowstone/main_translator.py (language detection)
• Modified: README.md (Gremlin examples)
• New: tests/integration/test_gremlin_integration.py

Documentation

Gremlin usage documented in:

• README.md (updated with Gremlin examples)
• src/yellowstone/gremlin/README.md (detailed Gremlin docs)

Ready for review.