fix: set default mock telemetry_consent to false to unblock Playwright

The mock settings used telemetry_consent: null which caused the consent
dialog to appear in every Playwright test, blocking the app shell.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/mock-tauri/mock-handlers.ts

@@ -81,7 +81,7 @@ let mockSettings: Settings = {
   github_token: null,
   github_username: null,
   auto_pull_interval_minutes: 5,
-  telemetry_consent: null,
+  telemetry_consent: false,
   crash_reporting_enabled: null,
   analytics_enabled: null,
   anonymous_id: null,