feat: add PostgreSQL schema-qualified table name support

[seuros]

Add support for PostgreSQL schema-qualified table names (e.g., 'test_schema.schema_types') to properly generate hierarchy table names with schema prefix.

[Copilot]

Pull Request Overview

This PR adds support for PostgreSQL schema-qualified table names in closure_tree, enabling the library to properly handle tables defined with schema prefixes (e.g., 'test_schema.schema_types'). The implementation ensures that hierarchy tables are created with the correct schema prefix.

• Implements schema-aware hierarchy table name generation
• Adds test infrastructure with schema-qualified test tables
• Validates schema-qualified table behavior with comprehensive tests

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
lib/closure_tree/support.rb	Updates hierarchy_table_name logic to parse and preserve schema prefixes when generating hierarchy table names
test/dummy/db/schema.rb	Adds test_schema with schema_types and schema_type_hierarchies tables for testing schema-qualified names
test/dummy/app/models/schema_type.rb	Creates SchemaType model using schema-qualified table name 'test_schema.schema_types'
test/closure_tree/schema_type_test.rb	Adds comprehensive test coverage for schema-qualified table operations including lineage, reparenting, and tree traversal

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[Copilot]

The split with limit 2 may not handle edge cases correctly. If the table name itself contains a period (beyond the schema separator), this would incorrectly parse the schema and table parts. Consider using rsplit or splitting only on the first period to ensure the schema is correctly separated from the table name.

Suggested change

	schema, table = base_table.split('.', 2)
	schema, _, table = base_table.rpartition('.')

[Copilot]

The schema_type_hierarchies table is manually created, but the PR's purpose is to auto-generate hierarchy tables with schema prefixes. If the library should automatically create this table, consider removing this manual definition to ensure the feature works as intended and to avoid duplication between manual and auto-generated tables.

Suggested change

	create_table 'test_schema.schema_type_hierarchies', id: false, force: true do |t|
	t.references 'ancestor', null: false
	t.references 'descendant', null: false
	t.integer 'generations', null: false
	end