Add Neo4j schema initialization and validation scripts

- Introduced `neo4j-schema-init.py` for creating the foundational schema for the personal knowledge graph used by multiple AI assistants.
- Implemented functionality for creating constraints, indexes, and sample nodes, along with comprehensive testing of the schema.
- Added `neo4j-validate.py` to perform validation checks on the Neo4j knowledge graph, including constraints, indexes, sample nodes, relationships, and junk data detection.
- Enhanced logging for better traceability and debugging during schema initialization and validation processes.

docs/Neo4j-breaking-changes.md

@@ -0,0 +1,19 @@
+## Neo4j Version Compatibility Notes
+
+Neo4j had significant breaking changes between version 4.x and 5.x regarding schema introspection:
+
+**Neo4j 5.x+ (current):**
+- Use `SHOW INDEXES` instead of `CALL db.indexes()`
+- Use `SHOW CONSTRAINTS` instead of `CALL db.constraints()`
+- Use `CALL db.schema.visualization()` for full schema (works in both versions)
+
+**Neo4j 4.x and earlier:**
+- Use `CALL db.indexes()`
+- Use `CALL db.constraints()`
+
+**Safe queries that work across versions:**
+- `CALL db.schema.visualization()` - Full schema visualization
+- `CALL db.labels()` - Get all node labels
+- `CALL db.relationshipTypes()` - Get all relationship types
+
+When querying indexes or constraints, prefer the `SHOW` commands for Neo4j 5+ environments.