Move the app's markup to the D components and Tailwind 4

The pages and components now use the daisyUI wrappers and the neo-* utilities
instead of Bulma and the neomorph classes:
- buttons are DButton, with pressed states as Active;
- nav links are btn / btn-active;
- the filter and composer selects are DSelect with a prefix icon;
- the composer's fields are DInput and DTextarea;
- the message options and scope pickers are DDropdown, which now close on an
  outside click and on Escape;
- the settings and admin sections are DCollapse;
- the dark-mode switch is a DToggle with sun and moon icons;
- the hue slider is a DRange on the rainbow track.

DropdownButton, OpenDownContainer and LoadingData are gone. The loader is
DLoading, whose animation runs; the old one's keyframes were never defined.
Icons coloured with Bulma's has-text-* now get daisyUI's text-info, success,
warning and error, which had no rules before.

Tailwind 3 to 4 fixes:
- space-x/y become gap, which also handles the flex-col-reverse feeds;
- !rounded-lg becomes rounded-lg!;
- drop-shadow becomes drop-shadow-sm;
- text-md becomes text-base.
The thread page marks its message with Content's new Highlighted parameter
rather than a second shadow size.

neo.css: a select's prefix icon gets the room daisyUI leaves for a span.label,
and the inner select lets the well show through.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

Components/ActionBar.razor

@@ -1,51 +1,47 @@
 @inherits LocalizableComponentBase
 
-<section class="flex flex-col space-y-4">
+<section class="flex flex-col gap-4">
 
 	@if (isPosting)
 	{
-		<div class="block p-3 md:p-4 neomorph rounded-xl is-nxsmall">
+		<div class="block p-3 md:p-4 rounded-xl neo-raised neo-xs">
 			<MessageUpsertForm OnMessageSubmit="OnMessageSubmit" />
 		</div>
 	}
 
-	<div class="flex justify-between space-x-3">
+	<div class="flex justify-between gap-3">
 
 		<EditForm Model="Filters">
-			<div class="field flex flex-row space-x-3">
+			<div class="flex flex-row gap-3">
 				@if (OnTimelineChanged.HasDelegate)
 				{
-					<div class="control has-icons-left">
-						<span class="icon is-left">
+					<DSelect TValue="TimelineType" class="w-auto" Value="Filters.TimelineType"
+							 ValueChanged="async v => await OnTimelineChange(v)" ValueExpression="() => Filters.TimelineType">
+						<Prefix>
 							<i class="@Filters.TimelineType.GetTimelineTypeIcon()"></i>
-						</span>
-						<span class="select is-rounded neoSelect">
-							<InputSelect TValue="TimelineType" Value="Filters.TimelineType"
-												 ValueChanged="async v => await OnTimelineChange(v)" ValueExpression="() => Filters.TimelineType">
-								@foreach (var timelineType in Enum.GetValues<TimelineType>())
-								{
-									<option value="@timelineType">@Localizer[timelineType.ToString()]</option>
-								}
-							</InputSelect>
-						</span>
-					</div>
+						</Prefix>
+						<ChildContent>
+							@foreach (var timelineType in Enum.GetValues<TimelineType>())
+							{
+								<option value="@timelineType">@Localizer[timelineType.ToString()]</option>
+							}
+						</ChildContent>
+					</DSelect>
 				}
 				@if (OnTimeSortingChanged.HasDelegate)
 				{
-					<div class="control has-icons-left">
-						<span class="icon is-left">
+					<DSelect TValue="TimeSortingType" class="w-auto" Value="Filters.TimeSortingType"
+							 ValueChanged="async v => await OnTimeSortChange(v)" ValueExpression="() => Filters.TimeSortingType">
+						<Prefix>
 							<i class="ion-md-funnel"></i>
-						</span>
-						<span class="select is-rounded neoSelect">
-							<InputSelect TValue="TimeSortingType" Value="Filters.TimeSortingType"
-												 ValueChanged="async v => await OnTimeSortChange(v)" ValueExpression="() => Filters.TimeSortingType">
-								@foreach (var timeSortingType in Enum.GetValues<TimeSortingType>())
-								{
-									<option value="@timeSortingType">@Localizer[timeSortingType.ToString()]</option>
-								}
-							</InputSelect>
-						</span>
-					</div>
+						</Prefix>
+						<ChildContent>
+							@foreach (var timeSortingType in Enum.GetValues<TimeSortingType>())
+							{
+								<option value="@timeSortingType">@Localizer[timeSortingType.ToString()]</option>
+							}
+						</ChildContent>
+					</DSelect>
 				}
 			</div>
 		</EditForm>
@@ -53,13 +49,10 @@
 		@if (OnMessageSubmit.HasDelegate)
 		{
 			<div>
-				<button class="button is-rounded @SUtility.IfTrueThen(isPosting, "neoBtnInsetPlain", "neoBtn")"
-							@onclick="OpenCloseMessageForm">
-					<span class="icon is-left">
-						<i class="ion-md-create"></i>
-					</span>
+				<DButton Active="isPosting" OnClick="OpenCloseMessageForm">
+					<i class="ion-md-create"></i>
 					<span>@Localizer["Post"]</span>
-				</button>
+				</DButton>
 			</div>
 		}
 		else