Replace inline modal-shadow styles on toasts, popups, and warning
banners with a shared `surface-popover` utility that uses the lighter
dropdown shadow instead of the heavier modal shadow. Apply the same
`shadow-dropdown` swap to the deployments indicator pill and the
server/deployment log floating menus. Remove now-unused console
header and error-contact-link rules from app.css, and add a test
asserting these surfaces consistently use the dropdown shadow.
