Fix Rsx_DateTime_Cast to handle microsecond timestamps after save()

Fix sidebar not displaying: use custom breakpoint classes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/RSpade/Core/Time/Rsx_DateTime_Cast.php

@@ -46,11 +46,15 @@ class Rsx_DateTime_Cast implements CastsAttributes
         // MySQL format "YYYY-MM-DD HH:MM:SS" - convert to ISO
         if (is_string($value) && preg_match('/^\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}/', $value)) {
             // Database stores in UTC, parse as UTC
-            $carbon = Carbon::createFromFormat(
-                strlen($value) > 19 ? 'Y-m-d H:i:s.v' : 'Y-m-d H:i:s',
-                $value,
-                'UTC'
-            );
+            // Handle fractional seconds: truncate to 3 digits for .v format (milliseconds)
+            // This handles microseconds (6 digits) from Laravel/Carbon after save()
+            if (strlen($value) > 19) {
+                $value = preg_replace('/(\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2})\.(\d{3})\d*/', '$1.$2', $value);
+                $format = 'Y-m-d H:i:s.v';
+            } else {
+                $format = 'Y-m-d H:i:s';
+            }
+            $carbon = Carbon::createFromFormat($format, $value, 'UTC');
             return $carbon->format('Y-m-d\TH:i:s.v\Z');
         }