Fix: Support floating point numbers in settings (Consensus Quorum Threshold)

Changed number type settings parsing from parseInt to parseFloat to
properly handle decimal values. Added step="any" attribute to number
inputs in the frontend when the setting has decimal min/max/default
values.

This ensures that Consensus Quorum Threshold and other floating point
settings (like METRICS_SAMPLING_RATE) can accept and save decimal
values like 0.5, 0.67, etc. instead of being truncated to integers.

- Updated includes/admin/admin-backend/routes/settings.js
- Updated includes/admin/routes/settings.js
- Updated includes/admin/admin-frontend/ui/settings.js

includes/admin/admin-backend/routes/settings.js

@@ -229,7 +229,9 @@ async function handleSettingsRoutes(req, res) {
           const meta = settingsMetadata[key];
           if (meta) {
             if (meta.type === 'number') {
-              const numValue = parseInt(value, 10);
+              // Use parseFloat to support both integers and floating point numbers
+              // parseFloat works for integers too (e.g., parseFloat("5") returns 5)
+              const numValue = parseFloat(value);
               if (isNaN(numValue)) {
                 errors.push(`${meta.label}: must be a number`);
                 continue;