feat: typescript plugin for import paths (#15779)

Adds `@payloadcms/typescript-plugin`, a TypeScript language service
plugin that validates PayloadComponent import paths in the IDE.


https://github.com/user-attachments/assets/2a8a8f73-a8fd-4e79-9dc4-795d817b5b75

It checks that referenced files and exports actually exist, provides
autocomplete for both file paths and export names, and supports
go-to-definition on component path strings. The plugin understands all
of Payload's path conventions including absolute paths relative to
baseDir, relative paths, tsconfig aliases, and package imports. It
auto-detects baseDir by finding the nearest payload config file and can
be overridden via tsconfig plugin options.