Rename the [Ee]xts dir to ext (#38852)

**WARNING:** This PR will probably blow up all in-flight PRs

at some point in the early days of CmdPal, two of us created seperate
`Exts` and `exts` dirs. Depending on what the casing was on the branch
that you checked one of those out from, it'd get stuck like that on your
PC forever.

Windows didn't care, so we never noticed.

But GitHub does care, and now browsing the source on GitHub is basically
impossible.

Closes #38081

src/modules/cmdpal/ext/SamplePagesExtension/SamplesListPage.cs

@@ -0,0 +1,92 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Microsoft.CommandPalette.Extensions;
+using Microsoft.CommandPalette.Extensions.Toolkit;
+
+namespace SamplePagesExtension;
+
+public partial class SamplesListPage : ListPage
+{
+    private readonly IListItem[] _commands = [
+
+        // List pages
+        new ListItem(new SampleListPage())
+        {
+            Title = "List Page Sample Command",
+            Subtitle = "Display a list of items",
+        },
+        new ListItem(new SampleListPageWithDetails())
+        {
+            Title = "List Page With Details",
+            Subtitle = "A list of items, each with additional details to display",
+        },
+        new ListItem(new SampleUpdatingItemsPage())
+        {
+            Title = "List page with items that change",
+            Subtitle = "The items on the list update themselves in real time",
+        },
+        new ListItem(new SampleDynamicListPage())
+        {
+            Title = "Dynamic List Page Command",
+            Subtitle = "Changes the list of items in response to the typed query",
+        },
+
+        // Content pages
+        new ListItem(new SampleContentPage())
+        {
+            Title = "Sample content page",
+            Subtitle = "Display mixed forms, markdown, and other types of content",
+        },
+        new ListItem(new SampleTreeContentPage())
+        {
+            Title = "Sample nested content",
+            Subtitle = "Example of nesting a tree of content",
+        },
+        new ListItem(new SampleCommentsPage())
+        {
+            Title = "Sample of nested comments",
+            Subtitle = "Demo of using nested trees of content to create a comment thread-like experience",
+            Icon = new IconInfo("\uE90A"), // Comment
+        },
+        new ListItem(new SampleMarkdownPage())
+        {
+            Title = "Markdown Page Sample Command",
+            Subtitle = "Display a page of rendered markdown",
+        },
+            new ListItem(new SampleMarkdownManyBodies())
+        {
+            Title = "Markdown with multiple blocks",
+            Subtitle = "A page with multiple blocks of rendered markdown",
+        },
+            new ListItem(new SampleMarkdownDetails())
+        {
+            Title = "Markdown with details",
+            Subtitle = "A page with markdown and details",
+        },
+
+        // Settings helpers
+        new ListItem(new SampleSettingsPage())
+        {
+            Title = "Sample settings page",
+            Subtitle = "A demo of the settings helpers",
+        },
+
+        // Evil edge cases
+        // Anything weird that might break the palette - put that in here.
+        new ListItem(new EvilSamplesPage())
+        {
+            Title = "Evil samples",
+            Subtitle = "Samples designed to break the palette in many different evil ways",
+        }
+    ];
+
+    public SamplesListPage()
+    {
+        Name = "Samples";
+        Icon = new IconInfo("\ue946"); // Info
+    }
+
+    public override IListItem[] GetItems() => _commands;
+}