fix(desktop): issue status cannot be changed from the GUI — only the CLI can set NIP-34 status events

### Summary

Issue status (kind:1630-1633) cannot be changed from the Buzz Desktop GUI. Clicking the status control on an issue does nothing — no status event is published. The only working path today is the CLI (`buzz issues status`), which is not a reasonable expectation for a human owner managing their project board.

### Steps to reproduce

1. Open an issue in a Buzz-hosted repo in Buzz Desktop (Projects view).
2. Try to change its status (e.g. Backlog → Resolved).
3. Nothing happens; the status event is not published and the UI stays unchanged.

### Expected

Changing an issue's status from the GUI should publish a NIP-34 status event (kind:1630-1633), signed by the current user, and the board should reflect it.

### Additional context

Per NIP-34, the winning status is the latest one from the root author or repo owner. Status events published by other parties (e.g. agents via CLI) are correctly ignored — which makes a working GUI setter the only practical way for the owner to close issues that agents can only mark from non-author keys.

Related gaps in the issue lifecycle: #4112 (statuses settable but not readable back), #2990 (no body editing).