refactor: consolidate dev and test command configuration into a new CommandsSection

- Introduced a new `CommandsSection` component to manage both development and test commands, replacing the previous `DevServerSection` and `TestingSection`.
- Updated the `SettingsService` to handle special cases for `devCommand` and `testCommand`, allowing for null values to delete commands.
- Removed deprecated sections and streamlined the project settings view to enhance user experience and maintainability.

This refactor simplifies command management and improves the overall structure of the project settings interface.

apps/server/src/services/settings-service.ts

@@ -837,6 +837,20 @@ export class SettingsService {
       delete updated.defaultFeatureModel;
     }
 
+    // Handle devCommand special cases:
+    // - null means delete the key (use auto-detection)
+    // - string means custom command
+    if ('devCommand' in updates && updates.devCommand === null) {
+      delete updated.devCommand;
+    }
+
+    // Handle testCommand special cases:
+    // - null means delete the key (use auto-detection)
+    // - string means custom command
+    if ('testCommand' in updates && updates.testCommand === null) {
+      delete updated.testCommand;
+    }
+
     await writeSettingsJson(settingsPath, updated);
     logger.info(`Project settings updated for ${projectPath}`);