Use Cash History report for true after-fee daily P&L, Fills FIFO as fallback

- Primary: Cash History report sums non-Fund-Transaction Deltas per day,
  capturing broker platform fees not present in the Fills report
- Fallback: Fills + FIFO used when Cash History 404s (passed/completed accounts)
- Extracts requestReport() as shared helper to reduce duplication
- debug PATCH endpoint now accepts optional `name` param to test any report

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

app/api/debug/route.ts

@@ -103,12 +103,12 @@ export async function PATCH(req: Request) {
 
         // Full report cycle
         if (payload.action === 'report') {
-            const { account, startDate, endDate } = payload;
+            const { account, startDate, endDate, name: reportName = 'Fills' } = payload;
             try {
                 let reportData = (await axios.post(
                     'https://rpt-demo.tradovateapi.com/v1/reports/requestreport',
                     {
-                        name: 'Fills', representationType: 'json', timezone: -300,
+                        name: reportName, representationType: 'json', timezone: -300,
                         params: [
                             { name: 'startDate', value: startDate },
                             { name: 'endDate',   value: endDate },