fix: resolve package roots to output paths

[kikiminyes]

Closes #182.

When a package-root alias resolved through packageId.subModuleName, the transformer used the source package directory as the module output directory. In declaration output with outDir, that could emit paths back to the source tree instead of the generated declaration tree.

This keeps package-root imports based on the resolved source file's emitted output directory, then trims any implicit package subpath such as subdir/main.d.ts so existing package-main behavior stays intact.

Validation:

• Reproduced Unexpected behavior in import a local package. #182 with the linked repro; the generated declaration still pointed at ../../../../../packages/components before this fix.
• Added a project-reference regression test covering a nested source importing a package root with outDir.
• yarn compile
• yarn test
• yarn prettier --check src/utils/resolve-module-name.ts test/tests/project-ref.test.ts test/projects/project-ref/tsconfig.base.json test/projects/project-ref/b/tsconfig.json test/projects/project-ref/b/deep/package-root.ts test/projects/project-ref/b/packages/pkg-root/index.ts test/projects/project-ref/b/packages/pkg-root/package.json
• yarn eslint src/utils/resolve-module-name.ts test/tests/project-ref.test.ts test/projects/project-ref/b/deep/package-root.ts test/projects/project-ref/b/packages/pkg-root/index.ts