- Add CreateEnum, DropEnum, AlterEnum diff models
- Add CreateEnumSQL, DropEnumSQL, AlterEnumSQL generators
- Add getEnums() to DBAdapterInterface
- Implement getEnums() in PostgresAdapter (pg_type + pg_enum)
- Stub getEnums() in MySQLAdapter and SQLiteAdapter (return [])
- Add getEnums() delegation in DBManager
- Add diffEnums() in DBSchema, wired before views/tables
- Update DiffSorter: enum drops before view drops, creates before view creates
- Add EnumSQLTest (7 tests) and DiffSorter enum ordering tests (3 tests)
- Update README and copilot-instructions

- Postgres E2E programmable_objects fixture: add order_status (CreateEnum),
  old_status (DropEnum), priority (AlterEnum) enum types to db1/db2-pgsql.sql
- AbstractComprehensiveTest: assert enum diffs in testProgrammableObjectsDiff
  for pgsql driver (CREATE TYPE, DROP TYPE IF EXISTS, ALTER presence)
- Record updated baseline: tests/expected/programmable_objects_pgsql_16.txt
  now includes enum SQL in correct sort order (drops before views, creates
  before views)
- PostgresDialectTest (new, 10 tests): quote escaping, getDriver, isMySQLOnly,
  DROP TRIGGER ... ON table syntax, dropIndex, addColumn, dropColumn
- SQLiteDialectTest (new, 8 tests): quote escaping, getDriver, isMySQLOnly,
  DROP TRIGGER (no ON clause), dropIndex, addColumn, dropColumn
- EnumSQLTest: 4 new edge-case tests — single-value enum, escaped quotes,
  AlterEnum drop-before-create ordering, DropEnum/CreateEnum inverse symmetry
- DiffSorterProgrammableTest: 4 new sort-order tests — DropEnum before
  AddTable, CreateEnum after AddTable before CreateView, full 7-item lifecycle