CmdPal: entirely redo the Run page (#39955)

This entirely rewrites the shell page. It feels a lot more like the old
run dialog now.

* It's got icons for files & exes
* it can handle network paths
* it can handle `commands /with args...`
* it'll suggest files in that path as you type
* it handles `%environmentVariables%`
* it handles `"Paths with\spaces in them"`
* it shows you the path as a suggestion, in the text box, as you move
the selection


References:
Closes #39044
Closes #39419
Closes #38298
Closes #40311


### Remaining todo's
* [x] Remove the `GenerateAppxManifest` change, and file something to
fix that. We are still generating msix's on every build, wtf
* [x] Clean-up code
* [x] Double-check loc
* [x] Remove a bunch of debug printing that we don't need anymore
* [ ] File a separate PR for moving the file (indexer) commands into a
common project, and re-use those here
* [x] Add history support again! I totally tore that out
  * did that in #40427 
* [x] make `shell:` paths and weird URI's just work. Good test is
`x-cmdpal://settings`

### further optimizations that probably aren't blocking
* [x] Our fast up-to-date is clearly broken, but I think that's been
broken since early 0.91
* [x] If the exe doesn't change, we don't need to create a new ListItem
for it. We can just re-use the current one, and just change the args
* [ ] if the directory hasn't changed, but we typed more chars (e.g.
`c:\windows\s` -> `c:\windows\sys`), we should cache the ListItem's from
the first query, and re-use them if possible.

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.WebSearch/FallbackExecuteSearchItem.cs

@@ -15,21 +15,26 @@ internal sealed partial class FallbackExecuteSearchItem : FallbackCommandItem
 {
     private readonly SearchWebCommand _executeItem;
     private static readonly CompositeFormat PluginOpen = System.Text.CompositeFormat.Parse(Properties.Resources.plugin_open);
+    private static readonly CompositeFormat SubtitleText = System.Text.CompositeFormat.Parse(Properties.Resources.web_search_fallback_subtitle);
+    private string _title;
 
     public FallbackExecuteSearchItem(SettingsManager settings)
         : base(new SearchWebCommand(string.Empty, settings) { Id = "com.microsoft.websearch.fallback" }, Resources.command_item_title)
     {
         _executeItem = (SearchWebCommand)this.Command!;
         Title = string.Empty;
+        Subtitle = string.Empty;
         _executeItem.Name = string.Empty;
-        Subtitle = string.Format(CultureInfo.CurrentCulture, PluginOpen, BrowserInfo.Name ?? BrowserInfo.MSEdgeName);
+        _title = string.Format(CultureInfo.CurrentCulture, PluginOpen, BrowserInfo.Name ?? BrowserInfo.MSEdgeName);
         Icon = Icons.WebSearch;
     }
 
     public override void UpdateQuery(string query)
     {
         _executeItem.Arguments = query;
-        _executeItem.Name = string.IsNullOrEmpty(query) ? string.Empty : Properties.Resources.open_in_default_browser;
-        Title = query;
+        var isEmpty = string.IsNullOrEmpty(query);
+        _executeItem.Name = isEmpty ? string.Empty : Properties.Resources.open_in_default_browser;
+        Title = isEmpty ? string.Empty : _title;
+        Subtitle = string.Format(CultureInfo.CurrentCulture, SubtitleText, query);
     }
 }

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.WebSearch/Properties/Resources.Designer.cs

@@ -248,5 +248,14 @@ namespace Microsoft.CmdPal.Ext.WebSearch.Properties {
                 return ResourceManager.GetString("settings_page_name", resourceCulture);
             }
         }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Search for &quot;{0}&quot;.
+        /// </summary>
+        public static string web_search_fallback_subtitle {
+            get {
+                return ResourceManager.GetString("web_search_fallback_subtitle", resourceCulture);
+            }
+        }
     }
 }

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.WebSearch/Properties/Resources.resx

@@ -178,6 +178,9 @@
   <data name="settings_page_name" xml:space="preserve">
     <value>Settings</value>
   </data>
+  <data name="web_search_fallback_subtitle" xml:space="preserve">
+    <value>Search for "{0}"</value>
+  </data>
   <data name="open_url_fallback_title" xml:space="preserve">
     <value>Open URL</value>
   </data>