Add GitHub Copilot instructions for repository

[Copilot]

Configures repository-specific instructions for GitHub Copilot coding agent following best practices.

Structure

Created .github/copilot-instructions.md and .github/instructions/ with targeted guidance:

• Main instructions - Project context: Neo4j-Databricks integration, graph model (7 node/7 relationship types), Unity Catalog conventions, security practices
• Python modules (applyTo: "*.py") - PySpark schemas, type hints, platform-agnostic design patterns
• Jupyter notebooks (applyTo: "*.ipynb") - Neo4j Spark Connector patterns, Databricks secrets management, Unity Catalog operations
• Documentation (applyTo: "*.md", excludeAgent: "coding-agent") - Markdown style, schema documentation templates

Key Patterns

Neo4j Spark Connector usage:

# Node extraction
df = spark.read \
    .format("org.neo4j.spark.DataSource") \
    .option("labels", node_label) \
    .load()

# Relationship extraction with source/target labels
df = spark.read \
    .format("org.neo4j.spark.DataSource") \
    .option("relationship", rel_type) \
    .option("relationship.source.labels", source_label) \
    .option("relationship.target.labels", dest_label) \
    .option("relationship.nodes.map", "false") \
    .load()

Unity Catalog naming convention:

# Three-level namespace: catalog.schema.table
TABLE_NAME = f"{CATALOG_NAME}.{SCHEMA_NAME}.customer"

Secrets management:

# Always use Databricks secrets, never hardcode
neo4j_password = dbutils.secrets.get("neo4j", "password")

Covers critical context: Databricks cluster must use "Dedicated" access mode for Neo4j Spark Connector, schema definitions must remain platform-agnostic, all table names follow retail_investment.retail_investment.* pattern.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>✨ Set up Copilot instructions</issue_title>
<issue_description>Configure instructions for this repository as documented in Best practices for Copilot coding agent in your repository.

</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes ✨ Set up Copilot instructions #2

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✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.