Initialize Black 7 PWA with React, Vite, and app icons

Sets up Vite + React + TypeScript with vite-plugin-pwa for offline support.
Adds app icon (line-drawn 7 on black) in all required sizes with a generation script.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.idea/.gitignore

@@ -0,0 +1,10 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Ignored default folder with query files
+/queries/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml