fix(create): complete catalogs in existing pnpm workspaces

[SaKaNa-Y]

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When I run vp create vite:application in an existing pnpm workspace without the required catalog entries, dependency installation fails with ERR_PNPM_CATALOG_ENTRY_NOT_FOUND_FOR_SPEC. The create flow writes catalog: references for vite and vite-plus into the new application's package.json but leaves their version definitions missing from pnpm-workspace.yaml. The generated application should have resolvable dependencies so installation can complete.

This change reuses the workspace's catalog selection when rewriting the new application, then adds its missing Vite+-managed catalog entries before installation. It supports default and named catalogs, preserves explicit catalog references and existing versions, and limits updates to the entries needed by the new application.

Verification

• The previously recorded focused test run passed all 7 regression tests, covering catalog selection, missing entries, and preservation of existing configuration.
• just snapshot-test create_existing_pnpm_workspace previously passed: it checks catalog output and lockfile creation, then runs a frozen installation and application build. Before the fix, it failed because installation produced no lockfile.
• GitHub CI: Lint and all Linux, macOS, and Windows CLI snapshot shards passed.

[SaKaNa-Y]

I found that using vp create to add an application to an existing pnpm workspace without the required catalog entries caused dependency installation to fail. The create flow rewrote the new application's dependencies to catalog references for vite and vite-plus, but did not ensure that the corresponding version entries existed in the workspace root.