ConfirmDialog locks body scroll via IJSRuntime + Bootstrap's
modal-open class on show, restores on hide. Escape key now closes
the dialog; default ConfirmButtonClass flipped from btn-danger to
btn-primary so non-destructive confirms aren't red. Destructive
callsites (Delete, Discard) get explicit ConfirmButtonClass="btn-danger".
ToastNotification adds aria-live="polite" + aria-atomic="true" on the
container and an optional autoDismissMs parameter on every Show* method.
LoadingSpinner text-muted -> text-secondary for contrast.
DataTable gains a clear (x) button on the search input and applies
disabled / aria-disabled directly to the pagination buttons.
NewFolderDialog splits backdrop and modal markup to match ConfirmDialog.
NavMenu wraps the nav list in an overflow-y scroll container so the
username/sign-out footer stays anchored, and section headers convert
from <li> to <div role="presentation">.
MainLayout adds a hamburger toggle for <lg viewports; sidebar collapses
via Bootstrap collapse data attributes.
App.razor extracts inline <style> block to a shared site.css; adds a
left-border accent on the active nav link; switches the reconnect
modal to modal-dialog-centered.
Login uses d-flex / min-vh-100 centering. NotAuthorizedView gets the
same centered layout plus the ScadaLink brand heading.
Sites.razor: only the new ConfirmButtonClass="btn-danger" follow-up.
