fix: preserve edited changes after export and on Dropbox reload

resetAllPendingRows was setting status to 'synced' instead of 'edited',
causing the merge logic on reload to skip those rows. Also keep 'edited'
and 'saved' statuses locally after export instead of clearing all.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/lib/supabase.ts

@@ -37,7 +37,7 @@ export interface ExcelRow extends Array<any> {}
 
 export interface SyncedRow {
   data: ExcelRow;
-  status?: 'pending' | 'synced';
+  status?: 'pending' | 'edited' | 'synced' | 'excel';
 }
 
 export async function getAllSyncedRows(): Promise<Record<string, SyncedRow>> {
@@ -208,7 +208,7 @@ export async function resetAllPendingRows(): Promise<boolean> {
           'Content-Type': 'application/json',
           'Prefer': 'return=minimal',
         },
-        body: JSON.stringify({ status: 'synced' })
+        body: JSON.stringify({ status: 'edited' })
       }
     );