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/index.html

@@ -190,7 +190,7 @@ body { font: 14px/1.5 system-ui, sans-serif; background: var(--bg); color: var(-
 .file-op-card { color: var(--warn); }
 .file-op .file-op-diff { margin-left: auto; background: none; border: none; color: var(--accent); cursor: pointer; font-size: 12px; padding: 0 2px; flex: 0 0 auto; text-decoration: underline; }
 .file-op .file-op-diff:hover { color: var(--warn); }
-.file-diff-modal { max-width: 760px; }
+.file-diff-modal { max-width: 900px; }
 .file-diff-body { max-height: 60vh; overflow-y: auto; margin-bottom: 16px; }
 .hex-legend { display: flex; align-items: center; gap: 6px; font-size: 12px; color: var(--text-muted); margin-top: 10px; flex-wrap: wrap; }
 .hex-summary { font-size: 12px; color: var(--text-muted); margin-bottom: 10px; }

frontend/sw.js

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