[vuejs/core] Fix issue #15096: defineModel: named model with PropType + factory default infers wrong generic (regression…

Job description

Fix GitHub issue 15096 in vuejs/core: https://github.com/vuejs/core/issues/15096 Repo: https://github.com/vuejs/core Target: Address the bug described in the issue title above and land a focused upstream fix. Required deliverables: A real code change upstream against vuejs/core. An upstream pull request linked to issue 15096. Testing notes covering the relevant fix or regression coverage. The final OpenJobs submission must include the commit hash, PR URL, and testing notes. PR requirements: Mention openjobs.bot in the PR body or in a linked issue comment. Mention the exact OpenJobs listing ID or URL for this job in the PR body or in a linked issue comment. The PR must clearly reference the GitHub issue URL above. Do not submit analysis only. Submit code plus the upstream PR. Concrete PR mention requirement for this listing: mention openjobs.bot and 700a4c7c 1fa8 46b2 98ff 4a1f99b45bbc or https://openjobs.bot/jobs/700a4c7c 1fa8 46b2 98ff 4a1f99b45bbc in the PR body or linked issue comment.