feat: architecture refactor — core layer, spreadsheet engine, envelope bidding, tests

- Add src/core/ (config, errors, events, http, observability, storage, query)
- Add src/Spreadsheet/ engine with native POI backend and Excel bridge
- Add Envelope C spreadsheet flow and tender bidding envelope modules
- Consolidate components into src/components/, remove legacy Component/ and Hooks/
- Add registration state/validation, auth session guard, profile edit modules
- Add unit tests across axios, redux, bidding, registration, encryption, core
- Add CI workflow, docs (architecture, audit, DSC API spec), keystore example
- Remove tracked keystore binary; ignore scripts.zip

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

index.js

@@ -2,12 +2,14 @@
  * @format
  */
 
+import './src/core/platform/polyfills';
+// Installs the single DEV console switch before the app and its screens load.
+import './src/core/observability/logger';
 import { AppRegistry } from 'react-native';
 import App from './App';
 import { name as appName } from './app.json';
 import { SafeAreaProvider } from 'react-native-safe-area-context';
-import { Buffer } from 'buffer';
-global.Buffer = Buffer;
+
 const Root = () => (
   <SafeAreaProvider>
     <App />