tl;dr: TypeScript 7 is a native Go port of the compiler, delivering 8-12x faster builds, reduced memory usage, and a rebuilt LSP-based language server with parallelized type-checking (configurable via new `--checkers`, `--builders`, and `--singleThreaded` flags). It's largely compatible with TS 6.0 but enforces stricter defaults and removes deprecated options like `target: es5`, `baseUrl`, and legacy module resolution modes. A stable programmatic API isn't ready yet, so tools like Vue, Svelte, Astro, and typescript-eslint must still rely on TS 6.0, which can run side-by-side via the new `@typescript/typescript6` package.