fix: bound automatic schema extraction input

[nkgotcode]

Description

Fixes #457.

This updates automatic schema extraction in the simple KG pipeline so schema extraction consumes splitter chunks instead of the full loader input. It also lets schema extraction accept chunk-list input and uses the first chunk for the schema prompt.

Type of Change

• Bug fix
• N/A: New feature
• N/A: Breaking change
• N/A: Documentation update
• N/A: Project configuration change

Complexity

Complexity: Low

How Has This Been Tested?

• Unit tests
• N/A: E2E tests
• N/A: Manual tests

uv run pytest tests/unit/experimental/pipeline/config/template_pipeline/test_simple_kg_builder.py tests/unit/experimental/components/test_schema.py -q

uv run ruff check src/neo4j_graphrag/experimental/components/schema.py src/neo4j_graphrag/experimental/pipeline/config/template_pipeline/simple_kg_builder.py tests/unit/experimental/pipeline/config/template_pipeline/test_simple_kg_builder.py tests/unit/experimental/components/test_schema.py

uv run ruff format --check src/neo4j_graphrag/experimental/components/schema.py src/neo4j_graphrag/experimental/pipeline/config/template_pipeline/simple_kg_builder.py tests/unit/experimental/pipeline/config/template_pipeline/test_simple_kg_builder.py tests/unit/experimental/components/test_schema.py

git diff --check

Checklist

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

• Unit tests have been updated
• CLA (https://neo4j.com/developer/cla/) has been signed
• CHANGELOG.md updated if appropriate
• N/A: Documentation has been updated
• N/A: E2E tests have been updated
• N/A: Examples have been updated
• N/A: New files have copyright header