refactor(board): modernize item and application select modals with SelectableCard (#6642)

Modernize board item, application, and integration selection flows with shared Mantine components, batch board actions, improved accessibility, and hardened persistence.

apps/docs/docs/management/boards/index.mdx

@@ -204,10 +204,13 @@ changes, Homarr asks whether to discard them. If the editor cannot load, the boa
   style={{ maxWidth: "100%" }}
 />
 
-While edit mode is active, **Add board content** opens the same Universal Create surface as the global header action and
-Spotlight. It lists the available actions directly and can add a widget, app, integration, Container, board, Workshop item, or Custom Widget when the
-current user and context allow it. Widget setup offers the main canvas, enabled rails, and existing Containers as
-destinations before the widget is created, so the common flow does not require a second move step.
+While edit mode is active, **Add board content** opens a menu for adding a widget, app, integration, or Container. The
+available actions respect the current user's permissions. Widget setup offers the main canvas, enabled rails, and existing
+Containers as destinations before the widget is created, so the common flow does not require a second move step.
+
+Hold `Ctrl` on Windows or Linux, or `⌘` on macOS, while clicking board items to select several at once. The selection
+toolbar can move the complete selection to another canvas, rail, or Container, delete it with an undo option, or clear the
+selection. A move is applied only when every selected item fits in the destination.
 
 The widget editor also lists its selected integrations. Users with full access can choose **Edit connection** to test,
 diagnose, and repair an integration without leaving the board. A successful repair refreshes the affected widget; the
@@ -227,11 +230,7 @@ During a pointer or touch interaction, Escape cancels the move or resize and res
 Invalid, outside, or otherwise forbidden drops are cancelled in the same way.
 The **Move / resize item** action in the edit menu remains available for precise numeric input.
 
-<img
-  src={keyboardTileEditingImage}
-  alt="A focused board tile in keyboard editing mode"
-  style={{ maxWidth: "100%" }}
-/>
+<img src={keyboardTileEditingImage} alt="A focused board tile in keyboard editing mode" style={{ maxWidth: "100%" }} />
 
 #### Preview
 

apps/docs/docs/widgets/today/index.mdx

@@ -1,34 +0,0 @@
----
-title: "Today"
-description: "Displays the current date and progress through the calendar."
-hide_title: true
----
-
-import { WidgetInteractionGuide } from "@site/src/components/widgets/interactions";
-
-import { AddingWidget } from "@site/src/components/widgets/adding";
-import { WidgetConfig } from "@site/src/components/widgets/configuration";
-import { WidgetHeader } from "@site/src/components/widgets/header";
-import { todayWidget } from ".";
-
-<WidgetHeader widget={todayWidget} categories={["Date", "Time"]} />
-
-The Today widget presents the current local date without duplicating a live clock. It progressively adds the week
-number, day of year, quarter, remaining days, and calendar progress as more space becomes available.
-
-The advanced view shows week, month, and year progress together with a twelve-month overview. Week numbers can follow
-your locale or the ISO 8601 convention. “Days after today” excludes the current day to keep the remaining-day count
-unambiguous.
-
-The widget runs entirely in your browser and does not send date or location data to an external service. It follows
-the timezone and locale of the device viewing the board, so viewers in different regions can see their own local date.
-
-<WidgetInteractionGuide />
-
-### Adding the widget
-
-<AddingWidget />
-
-### Configuration
-
-<WidgetConfig configuration={todayWidget.configuration} />

apps/docs/docs/widgets/today/index.ts

@@ -1,43 +0,0 @@
-import type { WidgetDefinition } from "@site/src/types";
-import { IconCalendarWeek } from "@tabler/icons-react";
-
-export const todayWidget: WidgetDefinition = {
-  icon: IconCalendarWeek,
-  name: "Today",
-  description: "Displays the current date and progress through the calendar.",
-  path: "../../widgets/today",
-  configuration: {
-    items: [
-      {
-        name: "Week numbering",
-        description: "Use locale-specific week numbering or ISO 8601 week numbers",
-        values: { type: "select", options: ["Use locale rules", "ISO 8601"] },
-        defaultValue: "Use locale rules",
-      },
-      {
-        name: "Show week number",
-        description: "Display the current week number when the widget has room",
-        values: { type: "boolean" },
-        defaultValue: "yes",
-      },
-      {
-        name: "Show day of year",
-        description: "Display the current day number within the year",
-        values: { type: "boolean" },
-        defaultValue: "yes",
-      },
-      {
-        name: "Show quarter",
-        description: "Display the current calendar quarter",
-        values: { type: "boolean" },
-        defaultValue: "yes",
-      },
-      {
-        name: "Show year progress",
-        description: "Display progress through the current year",
-        values: { type: "boolean" },
-        defaultValue: "yes",
-      },
-    ],
-  },
-};