feat: Add ArcadeDB backend driver

[lvca]

Summary

Adds ArcadeDB as a new graph database backend for Graphiti, as requested in #1259.

ArcadeDB is an open-source (Apache 2.0) multi-model DBMS that natively supports graph, document, vector (HNSW), and full-text search (Lucene) — all in a single engine. ArcadeDB 26.2.1+ ships the Neo4j Bolt wire protocol, allowing the existing neo4j Python async driver to connect directly with zero additional dependencies.

What's included

• ArcadeDBDriver — main driver using AsyncGraphDatabase (Bolt transport)
• 11 operation implementations — full coverage of all CRUD and search operations:
  • Entity, Episode, Community, Saga node operations
  • Entity, Episodic, Community, HasEpisode, NextEpisode edge operations
  • Search operations (fulltext, similarity, BFS, rerankers)
  • Graph maintenance operations
• ArcadeDB-specific SQL DDL for index creation (range indexes + Lucene fulltext indexes)
• GraphProvider.ARCADEDB enum value
• ArcadeDB branches in shared query builders (node_db_queries, edge_db_queries, graph_queries, search_filters)
• arcadedb optional dependency in pyproject.toml (empty — reuses neo4j core dependency)

Key design decisions

Concern	Approach
Transport	Reuses neo4j async driver via Bolt protocol — no new dependency
Embeddings	Stored as regular list properties (no db.create.setNodeVectorProperty())
Labels	Stored as node property (ArcadeDB has single-type-per-vertex)
Batch deletes	Direct DETACH DELETE (no Neo4j IN TRANSACTIONS syntax)
Vector search	Cosine similarity computed in Python via numpy; can be optimized with ArcadeDB's native vectorNeighbors()
Fulltext search	Uses CONTAINS predicates; can be enhanced with native Lucene index queries
Multi-label MATCH	Label-less MATCH (node {uuid: ...}) for polymorphic queries (like FalkorDB)

Usage

from graphiti_core.driver.arcadedb_driver import ArcadeDBDriver

driver = ArcadeDBDriver(
    uri="bolt://localhost:7687",
    user="root",
    password="arcadedb",
    database="graphiti",
)
await driver.build_indices_and_constraints()

# Docker quickstart
docker run -d -p 2480:2480 -p 7687:7687 \
  -e JAVA_OPTS="-Darcadedb.server.plugins=Bolt:com.arcadedb.server.bolt.BoltPlugin" \
  arcadedata/arcadedb

Why ArcadeDB for Graphiti

With Kùzu archived after the Apple acquisition (#1132), users looking for a self-contained, local-first graph + vector + fulltext backend now have ArcadeDB as an option:

• Graph traversal — native graph engine with O(1) traversal
• Vector similarity — built-in HNSW vector indexes
• Full-text search — Lucene-based fulltext indexes
• License — Apache 2.0 (permissive)
• Deployment — embedded or server mode, single JAR

Closes #1259

Test plan

• Unit tests for ArcadeDB driver class (session, query execution, index ops)
• Integration tests with ArcadeDB Docker container (arcadedata/arcadedb)
• Verify CRUD operations for all node and edge types
• Verify search operations (fulltext, similarity, BFS)
• Verify index creation via SQL DDL over Bolt
• Run make check (ruff + pyright)

🤖 Generated with Claude Code

[danielchalef]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[lvca]

I have read the CLA Document and I hereby sign the CLA