fix: publish readable-stream types dependency

[Serjik-Developer]

Summary

Move @types/readable-stream from devDependencies to dependencies.

The package emits TypeScript declarations that import and augment readable-stream. Consumers compiling those declarations need the type package installed transitively.

Verification

• npx tsc --project .

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Note

Low Risk
Packaging-only change with no application or runtime logic modified; slightly increases install footprint for all consumers.

Overview
Moves @types/readable-stream from devDependencies to dependencies so it is installed for consumers of the published package.

Published .d.ts output (including module augmentation in readable-stream.d.ts) references readable-stream types; without this package as a transitive dependency, TypeScript projects that depend on @metamask/object-multiplex can fail to resolve those types at compile time.

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