Adding a NEO4J_SAMPLE parameter to enable control of apoc.meta.schema sample size

[mimomenome]

Introduces a --sample CLI argument and NEO4J_SAMPLE environment variable to control the sample size used in APOC schema inspection queries. This allows limiting the number of nodes scanned for schema operations, improving performance on large graphs. Includes updates to config processing, server logic, and unit tests for sample precedence and validation.

Description

Type of Change

• [x ] New feature
• Bug fix
• Breaking change
• Documentation update
• Project configuration change

Complexity

• [ x] LOW
• MEDIUM
• HIGH

Complexity:

How Has This Been Tested?

• [ x] Unit tests
• Integration tests
• [x ] Manual tests

NOTE
Manual tests consist of using the build python module in another project to confirm MCP server still functions, schema is loaded when sample setting is None, and when setting is set to a value. Schema appears to be reduced in size when set to a low value (eg 1), but this has not been validated against an actual large graph to determine effect of reducing the sample size.

An additional improvement would be to add full logging of resulting schema node/property counts, and possibly expose an MCP tool that helps the user test which sample size produces optimal schema with enough context to inform cypher generation without requiring long load time.

Checklist

The following requirements should have been met (depending on the changes in the branch):

• [ x] Documentation has been updated
• [ x] Unit tests have been updated
• Integration tests have been updated
• [ x] Server has been tested in an MCP application
• CHANGELOG.md updated if appropriate