### Check existing issues - [x] I've verified that this bug isn't described by any existing issues. ### Bug description When a project has `name` in `charmcraft.yaml` and a separate `metadata.yaml` (without `name`), the packed `.charm` file contains a `metadata.yaml` with no `name` field. This makes the charm undeployable — Juju rejects it with `"metadata: name: expected string, got nothing"`. ### Steps to reproduce 1. Create a project with `name: my-charm` in `charmcraft.yaml` and a separate `metadata.yaml` that has `summary`, `description`, and relations but **no** `name` field. 2. Run `charmcraft pack --destructive-mode`. 3. Unzip the resulting `.charm` and inspect `metadata.yaml` — `name` is absent. 4. Attempt to deploy locally: `juju deploy ./my-charm_*.charm` → fails with `"metadata: name: expected string, got nothing"`. ### Environment charmcraft 4.0.1 (snap), destructive mode, Ubuntu 24.04 amd64. ### charmcraft.yaml ```yaml name: example-charm type: charm platforms: ubuntu@24.04:amd64: parts: charm: {} With a separate `metadata.yaml` containing `summary`, `description`, and relations but no `name`. ``` ### Log output ```shell juju.errors.JujuError: {"error":"cannot upload charm: invalid charm archive: metadata: name: expected string, got nothing","error-code":"bad request"} ```