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>

jest.config.js

@@ -1,3 +1,8 @@
 module.exports = {
   preset: 'react-native',
+  // The RN preset only transpiles react-native packages; these ESM-only deps
+  // (pulled in by Redux Toolkit) must be transformed too or jest can't parse them.
+  transformIgnorePatterns: [
+    'node_modules/(?!(jest-)?react-native|@react-native(-community)?|@react-navigation|@reduxjs/toolkit|immer|redux|redux-persist)/',
+  ],
 };