Refactor usage statistics to be a top-level setting (#1363)

This commit refactors the `usageStatisticsEnabled` setting from a sub-property of the `telemetry` configuration to a top-level setting. This change simplifies the configuration by decoupling usage statistics from the telemetry settings.

The documentation has also been updated to reflect this change.

packages/cli/src/config/config.ts

@@ -226,9 +226,8 @@ export async function loadCliConfig(
         process.env.OTEL_EXPORTER_OTLP_ENDPOINT ??
         settings.telemetry?.otlpEndpoint,
       logPrompts: argv.telemetryLogPrompts ?? settings.telemetry?.logPrompts,
-      usageStatisticsEnabled:
-        settings.telemetry?.usageStatisticsEnabled ?? true,
     },
+    usageStatisticsEnabled: settings.usageStatisticsEnabled ?? true,
     // Git-aware file filtering settings
     fileFiltering: {
       respectGitIgnore: settings.fileFiltering?.respectGitIgnore,

packages/cli/src/config/settings.ts

@@ -49,6 +49,7 @@ export interface Settings {
   contextFileName?: string | string[];
   accessibility?: AccessibilitySettings;
   telemetry?: TelemetrySettings;
+  usageStatisticsEnabled?: boolean;
   preferredEditor?: string;
   bugCommand?: BugCommandSettings;
   checkpointing?: CheckpointingSettings;