fix(create): migrate pack config in new workspace libraries

[SaKaNa-Y]

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vp create can add a library to an existing workspace without updating legacy pack configuration such as dts.tsgo: true. The library then fails to build with Cannot create property 'path' on boolean 'true'. Standalone creation already runs the migration that updates this configuration. The code that adds a workspace member skips that step.

Run the existing import and configuration migration when adding a workspace member, before updating lazy plugins. Full workspace migration still runs this step at the root. The generated library receives the current configuration without a separate conversion or a change to the external template.

Verification:

• The new regression test failed before the fix and passed after it. Running the rewrite twice produces the same file.
• Migration tests: 374 passed. Repository unit tests: 2198 passed, 1 skipped.
• vp check passed formatting, lint, and type checks.
• The new CLI test creates a workspace library from a template with legacy configuration. It builds the library and confirms JavaScript and declaration output.