Accounting: add report mode to buildium-payee-backfill

report mode pulls /v1/generalledger signed balances per account for the
window so imported books can be diffed against Buildium's authoritative GL
to verify completeness.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

supabase/functions/buildium-payee-backfill/index.ts

@@ -156,11 +156,46 @@ Deno.serve(async (req) => {
       if (gid) glIds.add(gid);
     }
     const allGlIds = [...glIds];
+    const CHUNK = 50;
+
+    // report mode: pull /v1/generalledger (signed amounts, debit +/credit −) and
+    // sum net movement per account for the window, to diff against our books.
+    if (mode === "report") {
+      const glMeta = new Map<string, { number: string; name: string; type: string }>();
+      const collectMeta = (g: any) => {
+        if (g?.Id) glMeta.set(String(g.Id), { number: String(g.AccountNumber ?? ""), name: String(g.Name ?? ""), type: String(g.Type ?? "") });
+        if (Array.isArray(g.SubAccounts)) for (const s of g.SubAccounts) collectMeta(s);
+      };
+      for (const g of glAccounts) collectMeta(g);
+      const netById = new Map<string, number>();
+      const txnIds = new Set<string>();
+      for (let i = 0; i < allGlIds.length; i += CHUNK) {
+        const params = new URLSearchParams();
+        params.set("accountingbasis", "Accrual");
+        params.set("startdate", dateFrom);
+        params.set("enddate", dateTo);
+        params.set("entitytype", "Association");
+        params.set("entityid", String(bAssocId));
+        for (const id of allGlIds.slice(i, i + CHUNK)) params.append("glaccountids", id);
+        const ledgers = await buildiumFetchAll("/v1/generalledger", clientId, clientSecret, params);
+        for (const ledger of ledgers) {
+          const gid = String(ledger.GLAccountId ?? ledger.GLAccount?.Id ?? "");
+          for (const e of ledger.Entries ?? []) {
+            netById.set(gid, (netById.get(gid) ?? 0) + (Number(e.Amount) || 0));
+            if (e.Id) txnIds.add(String(e.Id));
+          }
+        }
+      }
+      const rows = [...netById.entries()]
+        .map(([gid, net]) => ({ ...(glMeta.get(gid) ?? { number: "", name: gid, type: "" }), net: Math.round(net * 100) / 100 }))
+        .filter((r) => Math.abs(r.net) > 0.005)
+        .sort((a, b) => a.number.localeCompare(b.number));
+      return json({ mode, company: company.name, window: [dateFrom, dateTo], distinctTxns: txnIds.size, accounts: rows.length, rows });
+    }
 
     // Pull GL transactions for the window. /v1/generalledger/transactions is the
     // Journal view — one row per transaction with its Id, type and party data.
     const txById = new Map<string, any>();
-    const CHUNK = 50;
     for (let i = 0; i < allGlIds.length; i += CHUNK) {
       const params = new URLSearchParams();
       params.set("startdate", dateFrom);