Announcements Banner

[memtech3]

Make feature for showing announcement banners and linking to modal detail dialogs. Evaluate Saksham's Kung Fu Tea announcement banner code (currently commented out)

Implement as sitewide component.
Banner at top of page (above navbar) with x button to close and more details button/click handler to open a model details dialog.
Ensure any old commented out code related to this is removed before closing this issue

[memtech3]

Will be used for showcase, workshop, and informational announcements

[memtech3]

AI generated banner added as a stopgap. Need to review and implement properly after showcase.

Current known issues:

• When content is more than one line long, banner covers parts of navbar