218

[RAprogramm]

Closes #218.

Restores a compile-time-like schema guarantee for generated (runtime) SQL with one integration test per entity:

• {Entity}::SCHEMA — generated entity_core::schema::TableSchema const describing declared columns (name, DDL type, nullability)
• {Entity}::assert_schema(pool) — compares the declaration against information_schema.columns and reports all drifts at once (missing table/column, nullability, type family)
• entity-core gains a schema module (feature postgres): TableSchema/SchemaColumn/assert_table plus typed SchemaDrift/SchemaMismatch errors
• Type comparison is family-based: TEXT/VARCHAR/CHAR fold into one text family, parametrised types drop arguments, arrays compare as arrays, USER-DEFINED (enums) skip the type check while keeping presence/nullability
• The migrations type mapper is now compiled unconditionally (the migrations feature still gates its codegen), so the schema constant works on lean feature sets

Validated against a real consumer: six production entities asserted green against a live migrated database on the first run — including CHAR(3) columns declared as String, a TEXT[] array and three Postgres enums — plus a negative probe confirming a bogus column is reported.

[codecov]

Codecov Report

❌ Patch coverage is 63.88889% with 65 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
crates/entity-core/src/schema.rs	52.55%	65 Missing ⚠️

📢 Thoughts on this report? Let us know!