feat: replace mapping generation with checked copy utilities

cmd/go-omni/apigen/templates.go

@@ -56,10 +56,11 @@ factories for new projects. Named middleware factories run after svc.Init;
 implement Dependencies accessors on ServiceContext and New<Name>(deps) once.
 Unimplemented/nil factories fail startup and clean registered dependencies.
 Existing projects retain middleware: handlers until explicitly migrated.
-Optional mappings generate typed assignments in internal/mapping/mappingsGen.go;
-configure source/target types and explicit conversion rules after resolving module
-dependencies. Missing fields fail generation and --check. See GENERATION.md in
-the framework repository for composition, null/reference semantics and migration.
+Ordinary Logic uses the generated Request/Response types directly. Where an
+independent business type is needed, use ordinary Go or the optional copyx package.
+There are no mappings/mappingFiles settings or generated mapping files in v0.19.
+See COPY.md in the framework repository for copy policies and migration steps,
+and GENERATION.md for field composition and middleware factories.
 
 ## Run
 
@@ -145,8 +146,7 @@ internal/handler/<group>/     # generated binding and Logic adapters
 internal/logic/<group>/      # developer-owned business operations
 internal/repository/<group>/  # optional; repository: group creates editable seeds
 internal/middleware/         # typed dependency interface, factories and registry
-omni.gen.json                # developer-owned generator options and mappings
-internal/mapping/*Gen.go      # optional compile-checked struct mappings
+omni.gen.json                # developer-owned repository/middleware options
 docs/openapi.json             # generated OpenAPI 3.0.3
 .goOmni/apiManifest.json      # ownership and content hashes
 `+"```"+`