Transform class references in connect-migrate

[timostamm]

This updates the connect-migrate command to replace imports for a message class with a schema import, and update:

• "new" expressions to a create() call
• calls to the static methods fromBinary, fromJson, fromJsonString
• isMessage calls

When the identifier is used elsewhere, add a type import for the message type.
When the message is a well-known type, update to import from @bufbuild/protobuf/wkt.

In addition , this adds support for converting import aliases when running the migrate tool. The same alias scheme is applied to the Schema imports added by the migration tool.

For example:

import { Foo as MyFoo } from "./foo_pb.js";` --> `import { FooSchema as MyFooSchema } from "./foo_pb.js";

[timostamm]

CI failures appear to be an issue with npmjs.com. npm ci fails with

Invalid response body while trying to fetch https://registry.npmjs.org/typescript: aborted
npm error network This is a problem related to network connectivity.

Everything passes locally, so I'm going to merge.