Most WebAssembly articles talk about performance. Yours runs 5x faster than pure JavaScript. Great. This one is about something different: how Wasm's sandboxed execution model makes certain privacy failures structurally impossible -- and how we built 90+ browser tools around that property. The Problem We Were Solving When someone uses iLovePDF, Smallpdf, or Adobe Acrobat Online to process a PDF, their file travels to a remote server, gets processed, and sits there until "del...