Change simulation date from month to year period

From January 2022 to 2022 to fix cotisation maladie/ex-CICE result

src/routes/__layout.svelte

@@ -70,7 +70,7 @@
   const firstWaterfallShown: Writable<boolean> = writable(false)
   setContext("firstWaterfallShown", firstWaterfallShown)
 
-  const date = writable("2022-01-01") // new Date().toISOString().split("T")[0]
+  const date = writable("2022") // new Date().toISOString().split("T")[0]
   setContext("date", date)
 
   const showNulls = writable(false)