[NFR]: Schema Fixtures

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Motivation

The test-fixture mechanism currently called "migrations" is duplicated wholesale across cphalcon and phalcon, and the artifact it produces is already consumed by talon - but produced outside it. The contract sits on the wrong side of the boundary.

Current-state facts

The duplication

• tests/support/Migrations/ holds 39 files in each project, byte-for-byte identical between cphalcon and phalcon.
• bin/generate-db-schemas.php (103 lines) is duplicated in both.
• AbstractMigration.php is 213 lines.
• 29 of the 39 classes define insert().

The split seam

Talon already owns the entire consumption side:

Settings::get('dump_file')            src/Settings.php:177
  -> DatabaseTrait                     src/Traits/DatabaseTrait.php:67
  -> Connection::loadSchema($file)     src/Database/Connection.php:79
  -> StatementSplitter::split()        src/Database/StatementSplitter.php
  -> exec

dump_file is set per driver in resources/phpunit.{mysql,mariadb,pgsql,sqlite}.xml.

The producer - bin/generate-db-schemas.php - lives in cphalcon/phalcon. Talon consumes a file format it does not define.

Implementation

Decision	Choice	Rationale
Naming	Schema, not Migration	These are not migrations. RollbackTestMigration tests transaction
Namespace	Phalcon\Talon\Database\Schema	Sits alongside the Database\* components it depends on.
What moves to talon	Base class, generator, discovery/ordering	Talon already owns connection, dialect, splitting and assertions. This is the missing half of an open seam.
What stays in the projects	The 39 concrete classes	They describe Phalcon's test data. Talon must stay usable by anyone.
Per-dialect raw SQL	Keep	A declarative DSL rebuilds phinx's Table API and cannot honestly express auto_increment/autoincrement/serial, pg sequences, SET FOREIGN_KEY_CHECKS=0, comment on, or tables absent from a dialect.
Statement lists	list<string>, developer-ordered	See below.
drop in the statement list	Removed	See below.
sqlsrv	Dropped	Dead weight on all 39 classes; commented out in the generator; absent from Dialect. May be reintroduced later, but not expected.
addTable() dependencies	None - standalone only, enforced	Caller issues a second addTable() with dependencies already satisfied. No transitive resolution. Enforced rather than documented - see the FK-strictness asymmetry below.
Scope ceiling	Fixtures only	No version numbers, no up/down, no state table, no --target. .

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Resolved in #34