added edit page and revised edit form

src/lib/stores/journalStore.js

@@ -116,3 +116,8 @@ export function addJournal(entry) {
 export function removeJournal(id) {
   journals.update((entries) => entries.filter((e) => e.id !== id));
 }
+
+/** @param {JournalEntry} updated */
+export function updateJournal(updated) {
+  journals.update((entries) => entries.map((e) => e.id === updated.id ? updated : e));
+}