[Feature]: Calendar

### Problem to solve

As a space enthusiast, I want a clear calendar of space events so I can plan my hobby around them.

### Desired outcome

The website has a calendar of events

### Proposed solution

_No response_

### Alternatives considered

_No response_

### Additional context

_No response_

### Before submitting

- [x] I searched existing issues and did not find an equivalent request.

Start by reviewing the existing website structure and how it currently represents space-related content. Define the event source, calendar view, and required event details before implementation. Done means the website provides a usable calendar of space events, but the issue does not specify its data or behavior.

Written by the indexing model from the issue text.