Add table partitioning support for MySQL and PostgreSQL

[dereuromark]

Summary

This PR adds support for PARTITION BY (RANGE, LIST, HASH, KEY) clauses when creating tables and managing partitions on existing tables.

Features

• RANGE, RANGE COLUMNS, LIST, LIST COLUMNS, HASH, KEY partitioning types
• Composite partition keys
• Add/drop partitions on existing tables
• PostgreSQL declarative partitioning with auto-generated partition table names
• Expression-based partitioning via Literal class

New Classes

• Partition: Value object for partition configuration
• PartitionDefinition: Value object for individual partition definitions
• AddPartition: Action for adding partitions to existing tables
• DropPartition: Action for dropping partitions

New Table Methods

• partitionBy(): Define partitioning on new tables
• addPartition(): Add partition definitions when creating tables
• addPartitionToExisting(): Add partition to existing partitioned tables
• dropPartition(): Remove partition from existing tables

Usage Example

$this->table('orders', ['id' => false, 'primary_key' => ['id', 'order_date']])
    ->addColumn('id', 'integer', ['identity' => true])
    ->addColumn('order_date', 'date')
    ->partitionBy(Partition::TYPE_RANGE_COLUMNS, 'order_date')
    ->addPartition('p2022', '2023-01-01')
    ->addPartition('p2023', '2024-01-01')
    ->addPartition('pmax', 'MAXVALUE')
    ->create();

Notes

• MySQL requires partition columns in the primary key
• MySQL's RANGE and LIST only work with integer expressions - use RANGE COLUMNS/LIST COLUMNS for DATE/STRING columns
• KEY partitioning is MySQL-only
• SQLite does not support partitioning (throws RuntimeException)

Test plan

• Unit tests for Partition and PartitionDefinition classes
• Integration tests for MySQL adapter (RANGE COLUMNS, LIST COLUMNS, HASH, KEY, integer RANGE, expression-based)
• All existing MySQL adapter tests pass
• CI should verify PostgreSQL tests

🤖 Generated with Claude Code

[dereuromark]

CI Status Update:

• ✅ PHPStan & PHPCS: Passing
• ✅ MySQL tests: Passing (all PHP versions)
• ✅ MariaDB tests: Passing (all PHP versions)
• ✅ SQLite tests: Passing (all PHP versions)
• ❌ PostgreSQL tests: Failing - but this is a pre-existing failure on the 5.x branch itself (see run #19602773442). The failure is in BakeMigrationSnapshotCommandTest::testPluginBlog related to timestamp vs timestampfractional type detection, completely unrelated to the partitioning feature.

The partitioning implementation is complete and working correctly for all supported databases.