fix: resolve graph adapter runtime crash and parameter bugs

[sigfawn]

This PR addresses critical functional bugs in GraphDatabaseAdapter.ts that prevented the graph backend from initializing or performing semantic searches.

1. ESM Compatibility Fix

• Problem: The adapter was using require('fs') inside an ESM module, which causes a ReferenceError in pure ESM environments.
• Fix: Replaced require with a standard import * as fs at the top of the file.

2. Cypher Parameter Support

• Problem: The query() method signature did not accept parameters, making it impossible to perform safe, parameterized queries.
• Fix: Updated the query() signature to accept params?: Record<string, any> and pass them to the underlying database engine.

3. Functional Search Fix

• Problem: searchSimilarEpisodes() used the `` placeholder in its Cypher string but failed to pass the actual embedding data. This caused a 100% failure rate for graph-based semantic memory recall.
• Fix: Corrected the call to pass { embedding } as a parameter map.

4. Data Type Flexibility

• Improvement: Updated property definitions from string only to any to better reflect the schema-less nature of the graph database while maintaining existing serialization for safety.

Result: The RuVector Graph backend is now functional for initialization and episodic memory retrieval.