CmdPal: Add actionable hint to empty results in File Search extension (#41982)

## Summary of the Pull Request

This PR improves the user experience when no indexed files match the
query in the File Search extension.

- Show a hint on the empty results page when no indexed files are found.
- Provide fallback actions:
- Search entire PC – opens new File Explorer window with the query
searched in This PC.
- Open Windows Search settings – navigates to Windows Search settings to
review indexed locations.

<img width="1719" height="1072" alt="image"
src="https://github.com/user-attachments/assets/51bd7b4a-563f-4339-b179-8125c057b0af"
/>


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## PR Checklist

- [x] Related to: #38509
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

<!-- Provide a more detailed description of the PR, other things fixed,
or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments

<!-- Describe how you validated the behavior. Add automated tests
wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed

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

@@ -96,6 +96,15 @@ namespace Microsoft.CmdPal.Ext.Indexer.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Open Windows Search settings.
+        /// </summary>
+        internal static string Indexer_Command_OpenIndexerSettings {
+            get {
+                return ResourceManager.GetString("Indexer_Command_OpenIndexerSettings", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Open path in console.
         /// </summary>
@@ -123,6 +132,15 @@ namespace Microsoft.CmdPal.Ext.Indexer.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Search all files.
+        /// </summary>
+        internal static string Indexer_Command_SearchAllFiles {
+            get {
+                return ResourceManager.GetString("Indexer_Command_SearchAllFiles", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Show in folder.
         /// </summary>
@@ -187,7 +205,8 @@ namespace Microsoft.CmdPal.Ext.Indexer.Properties {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Tip: Improve your search result using filters like in Windows Explorer. (For example: type:directory).
+        ///   Looks up a localized string similar to Nothing was found in the indexed locations.
+        ///You can try searching all files on this PC or adjust your indexing settings..
         /// </summary>
         internal static string Indexer_NoResultsMessageTip {
             get {
@@ -195,6 +214,15 @@ namespace Microsoft.CmdPal.Ext.Indexer.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Tip: Refine your search using filters, just like in File Explorer (e.g., type:directory)..
+        /// </summary>
+        internal static string Indexer_NoSearchQueryMessageTip {
+            get {
+                return ResourceManager.GetString("Indexer_NoSearchQueryMessageTip", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Search for files and folders....
         /// </summary>