Files view: widen the change-details modal (760px -> 900px)

- the before/after hex views (16 bytes per row, two side by side) had little
  room at 760px; the modal's max-width is now 900px (the base `.modal` width
  of 90% still keeps it inside the viewport on smaller screens)
- SW cache simtrace-analyser-v69 (cosmetic, no version bump)

frontend/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'simtrace-analyser-v68';
+const CACHE = 'simtrace-analyser-v69';
 
 const PRECACHE = [
     'index.html',