chore: project scaffold, build config, scripts and README

Bun + SvelteKit (static adapter) + Electron project files, icon resources,
dev/e2e/bench scripts and the README documenting the app.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,10 @@
+node_modules/
+.svelte-kit/
+build/
+dist/
+.DS_Store
+*.log
+
+# one-off patch scripts, kept out of the way
+old-patches/
+*.bak