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>

metro.config.js

@@ -26,14 +26,6 @@ const config = {
       /node_modules\/.*\/android\/build\/.*/,
       /node_modules\/.*\/android\/\.gradle\/.*/,
     ]
-  },
-  watcher: {
-    additionalExclusions: [
-      // Also exclude from the watcher layer for safety
-      "**/android/.cxx/**",
-      "**/android/build/**",
-      "**/android/.gradle/**",
-    ]
   }
 };