Issue: cakephp/phinx#2364

SQLite adapter incorrectly adds AUTOINCREMENT keyword to integer columns when changing a table's primary key, even when not explicitly specified.

Changes Made

1. Fixed SqliteAdapter::getAddPrimaryKeyInstructions() (src/Db/Adapter/SqliteAdapter.php:1338-1372)

• Before: Automatically added AUTOINCREMENT to ALL INTEGER columns when making them primary keys
• After: Only adds AUTOINCREMENT if the column already had it in the original table definition
• Uses regex to detect the presence of AUTOINCREMENT keyword in the current CREATE TABLE SQL

The fix was verified to:

• ✅ No longer add AUTOINCREMENT when changing PK to a column that didn't have it
• ✅ Maintain backward compatibility with existing tests
• ✅ Match the behavior of other adapters (MySQL, Postgres, SQL Server)