fix(dev): export AssemblyScript types and tsdown defineConfig

[LuanRoger]

This pull request updates project dependencies and configuration files to improve TypeScript compatibility and streamline the build process. The most important changes involve moving assemblyscript from a development dependency to a runtime dependency, updating TypeScript configuration references, and ensuring type definitions are correctly copied during builds.

Dependency management:

• Moved assemblyscript from devDependencies to dependencies in package.json, ensuring it is available at runtime rather than just during development. [1] [2]

TypeScript configuration updates:

• Removed the assemblyscript/std/portable.json extension from src/dev/tsconfig/base.json, decoupling the TypeScript configuration from AssemblyScript-specific settings.
• Changed the types field in src/dev/tsconfig/base.json from ["portable"] to ["types"] to reference the project's own type definitions instead of AssemblyScript's.

Build process improvements:

• Updated the copy array in tsdown.config.ts to include copying src/dev/types/index.d.ts to the build output, ensuring custom type definitions are available in the distribution.

Code organization:

• Re-exported defineConfig from tsdown in src/dev/tsdown/index.ts, making it available for use elsewhere in the project.