[Bug]: Dialog close event timing change breaks applications expecting immediate event dispatch

### Code of conduct

- [x] I agree to follow this project's code of conduct.

### Impacted component(s)

Dialog

### Library version

1.0.3

### Expected behavior

SWC dialogs actually have two distinct events for different purposes:
- close event - Should indicate the start of dialog closing (immediate)
- sp-closed event - should indicate the completion of dialog closing (after animations)

### Actual behavior

close event indicates the start of dialog close instead of end

### Screenshots

_No response_

### What browsers are you seeing the problem in?

_No response_

### How can we reproduce this issue?

1. Go to https://stackblitz.com/edit/vitejs-vite-vuew3kbr?file=src%2Fmy-element.ts
2. Add a close event on Dialog
3. console logs the two events

### Sample code or abstract reproduction which illustrates the problem

https://github.com/adobe/spectrum-web-components/pull/4937

### Severity

SEV 2

### Logs taken while reproducing problem

_No response_

### Would you like to track this issue in Jira?

- [ ] Yes, please tell me the ticket number!

Start with the Dialog implementation and the StackBlitz reproduction linked in the issue, then compare the event behavior discussed in pull request #4937. Verify that the close event is dispatched at the expected lifecycle point and that sp-closed still represents completion after animations; reproduce the two console logs to confirm the timing.

Written by the indexing model from the issue text.