perf: set global prisma transaction timeouts and reduce transaction scope (#2607)

Configure default transaction options (5s maxWait, 10s timeout) on the
PrismaClient instead of per-transaction overrides. Move side effects
like email sending, webhook triggers, and job dispatches out of
$transaction blocks to avoid holding database connections open during
network I/O.

Also extracts the direct template email into a background job and fixes
a bug where prisma was used instead of tx inside a transaction.

packages/prisma/index.ts

@@ -13,6 +13,10 @@ const prisma = remember(
   () =>
     new PrismaClient({
       datasourceUrl: getDatabaseUrl(),
+      transactionOptions: {
+        maxWait: 5000,
+        timeout: 10000,
+      },
     }),
 );