[CmdPal] Settings UX tweaks (#42303)

## Summary of the Pull Request

Clean up of the Settings app with some minor styling changes.

- Moved activation key related settings into the Activation expander.
- On the Extensions page, seperated the alias settings for improved a11y
- Added a card to the extensions settings frame

<img width="1051" height="935" alt="image"
src="https://github.com/user-attachments/assets/05ae5794-8e30-4af0-aa38-a3f600aa6749"
/>

## PR Checklist

- [ ] Closes: #xxx
- [ ] **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

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---------

Co-authored-by: Jiří Polášek <me@jiripolasek.com>

src/modules/cmdpal/Microsoft.CmdPal.UI/Strings/en-us/Resources.resw

@@ -257,8 +257,8 @@ Right-click to remove the key combination, thereby deactivating the shortcut.</v
     <value>Disabled</value>
     <comment>Displayed when an extension is disabled</comment>
   </data>
-  <data name="ExtensionEnableCard.Header" xml:space="preserve">
-    <value>Enable this extension</value>
+  <data name="ExtensionEnable.Text" xml:space="preserve">
+    <value>Enable</value>
     <comment>Displayed on a toggle controlling the extension's enabled / disabled state</comment>
   </data>
   <data name="ExtensionEnableCard.Description" xml:space="preserve">
@@ -312,7 +312,13 @@ Right-click to remove the key combination, thereby deactivating the shortcut.</v
     <value>Alias</value>
   </data>
   <data name="Settings_ExtensionPage_Alias_SettingsCard.Description" xml:space="preserve">
-    <value>Typing this alias will navigate to this command. Direct aliases navigate as soon as you type the alias. Indirect aliases navigate after typing a trailing space.</value>
+    <value>A short keyword used to navigate to this command.</value>
+  </data>
+  <data name="Settings_ExtensionPage_AliasActivation_SettingsCard.Header" xml:space="preserve">
+    <value>Alias activation</value>
+  </data>
+  <data name="Settings_ExtensionPage_AliasActivation_SettingsCard.Description" xml:space="preserve">
+    <value>Choose when the alias runs. Direct runs as soon as you type the alias. Indirect runs after a trailing space.</value>
   </data>
   <data name="Settings_ExtensionPage_Builtin_SettingsCard.Header" xml:space="preserve">
     <value>Built-in</value>
@@ -429,12 +435,15 @@ Right-click to remove the key combination, thereby deactivating the shortcut.</v
     <value>Close</value>
     <comment>Close as a verb, as in Close the application</comment>
   </data>
-  <data name="Settings_ExtensionPage_Alias_ToggleSwitch.OnContent" xml:space="preserve">
+  <data name="Settings_ExtensionPage_Alias_DirectComboBox.Content" xml:space="preserve">
     <value>Direct</value>
   </data>
-  <data name="Settings_ExtensionPage_Alias_ToggleSwitch.OffContent" xml:space="preserve">
+  <data name="Settings_ExtensionPage_Alias_InDirectComboBox.Content" xml:space="preserve">
     <value>Indirect</value>
   </data>
+  <data name="Settings_ExtensionPage_Alias_PlaceholderText.PlaceholderText" xml:space="preserve">
+    <value>Enter alias</value>
+  </data>
   <data name="StatusMessagesButton.[using:Microsoft.UI.Xaml.Automation]AutomationProperties.Name" xml:space="preserve">
     <value>Show status messages</value>
   </data>
@@ -454,7 +463,7 @@ Right-click to remove the key combination, thereby deactivating the shortcut.</v
     <value>Trigger reload of the extension externally with the x-cmdpal://reload command</value>
   </data>
   <data name="ForDevelopersSettingsHeader.Text" xml:space="preserve">
-    <value>For Developers</value>
+    <value>For developers</value>
   </data>
   <data name="UntitledPageTitle" xml:space="preserve">
     <value>an untitled</value>