migration-codegen

# Migration Code Generation ## Read First - `src/lib/codegen/` and its Laravel, TypeORM, and Django generators. - `src/lib/exporter/` for dialect-specific SQL generation. - `src/lib/types.ts` for columns, indexes, and edge metadata. - `src/lib/utils.ts` for IDs and relationship helpers. ## Change Rules 1. Keep framework conventions explicit: Laravel timestamps and inferred foreign-key names, TypeORM's SQL parsing assumptions, and Django's `yourapp` placeholder. 2. Validate identifier quoting, nullable/default/generated columns, indexes, composite foreign keys, on-delete/on-update behavior, and table ordering. 3. Do not assume generated SQL has one formatting shape. If a generator parses SQL, keep the parser tolerant of the SQL it emits and test alterations as well as creates. 4. Preserve hyphenated IDs when resolving handles and columns. Never use `split("-")[0]` as a column-ID parser. 5. Treat output as a candidate artifact. Do not claim a migration is executable without reviewing or executing it against the target framework/database. ## Verification - Generate artifacts for empty, single-table, indexed, related, composite-key, and altered schemas. - Inspect generated files for valid syntax, deterministic naming, and correct foreign-key direction. - Exercise each supported database type where the generator accepts it. - Run type-check, lint, and build; manually review generated output because no generated SQL test runner is configured.