fix(panchang): Abhijit Muhurta is null on Wednesdays and the screen assumed it never was

The field is typed object-or-null because Abhijit coincides with Dur
Muhurta on Wednesdays per Muhurta Chintamani, so reading .start off it
threw one day in seven. Render the window when present and say plainly
when there is none, rather than printing a broken range.

Caught by the typecheck on a routine SDK bump, which is the generated
client correctly reporting a nullability the screen never handled.

Author: ph33nx

app/(tabs)/panchang.tsx

@@ -125,8 +125,11 @@ export default function PanchangScreen() {
               <Text className="text-base font-bold text-zinc-900 dark:text-white">
                 {result.rahuKaal.start} - {result.rahuKaal.end}
               </Text>
+              {/* Abhijit Muhurta is null on Wednesdays, when it coincides with Dur Muhurta. */}
               <Text className="text-xs text-zinc-500 dark:text-zinc-500 mt-2">
-                Abhijit Muhurta {result.abhijitMuhurta.start} - {result.abhijitMuhurta.end}
+                {result.abhijitMuhurta
+                  ? `Abhijit Muhurta ${result.abhijitMuhurta.start} - ${result.abhijitMuhurta.end}`
+                  : 'No Abhijit Muhurta today'}
               </Text>
             </View>
           </View>