fix: inline source content in sourcemaps to prevent missing source warnings (#5)
When vinext is installed from npm, the .ts source files aren't in the
package but .js.map files reference them, causing Vite to log many
'points to missing source files' warnings.
Adding inlineSources: true to tsconfig embeds the original TypeScript
source content directly in the .js.map files so no separate .ts files
are needed.
Fixes #2