Fix Dashboard Disk card showing blank value and wrong bar width

The Dashboard template (index.html) calls ramPct() and diskPct() as
methods, but dashboardPage() never defined them - Alpine threw a
silent ReferenceError on these bindings. This left the Disk card's big
percentage value empty, and since the bar's :style binding also failed,
the fill defaulted to a near-full width regardless of actual usage
(visible as an orange bar that looked ~90% full despite '6.5 GB /
57.1 GB' being ~11%). RAM's big value was unaffected since it reads
stats.ram.used directly (fmtBytes), but its bar width had the same
issue. Added both methods, computing percentage from
stats.{ram,disk}.{used,total} which /api/dashboard/stats already
provides.

Author: BrowserlessAPI

web/static/js/app.js

@@ -231,6 +231,8 @@ function dashboardPage() {
       if(r.ok) this.services=r.services.slice(0,8);
     },
     go(page){ window.dispatchEvent(new CustomEvent('nav',{detail:{page}})); },
+    ramPct()  { const r=this.stats.ram;  return (r && r.total) ? Math.round(r.used/r.total*100) : 0; },
+    diskPct() { const d=this.stats.disk; return (d && d.total) ? Math.round(d.used/d.total*100) : 0; },
   };
 }