feat(FN-281): add payment_success and payment_failed PostHog events (+1 more)

Commits merged:
- fix(FN-281): make result search param truly optional to fix typecheck
- feat(FN-281): add payment_success and payment_failed PostHog events

Files changed:
apps/api/package.json                              |    1 +
 apps/api/src/app.module.ts                         |    2 +
 apps/api/src/payments/payments.service.spec.ts     |   99 +-
 apps/api/src/payments/payments.service.ts          |   40 +
 apps/api/src/posthog/posthog.module.ts             |    9 +
 apps/api/src/posthog/posthog.service.ts            |   64 ++
 .../web/src/components/payment/payment-content.tsx |   24 +-
 apps/web/src/routeTree.gen.ts                      | 1110 ++++++++++----------
 apps/web/src/routes/dashboard/subscription/pay.tsx |   24 +-
 packages/config/src/index.ts                       |    4 +
 pnpm-lock.yaml                                     |   30 +
 11 files changed, 827 insertions(+), 580 deletions(-)

Fusion-Task-Id: FN-281

apps/web/src/routes/dashboard/subscription/pay.tsx

@@ -9,16 +9,26 @@ const PaymentContent = lazy(() =>
 );
 
 export const Route = createFileRoute("/dashboard/subscription/pay")({
-  validateSearch: (search: Record<string, unknown>) => ({
-    plan: (search.plan as string) || "",
-    period: ((search.period as string) || "monthly") as "monthly" | "yearly",
-    brands: (search.brands as string) || "",
-  }),
+  validateSearch: (search: Record<string, unknown>) => {
+    const params: {
+      plan: string;
+      period: "monthly" | "yearly";
+      brands: string;
+      result?: string;
+    } = {
+      plan: (search.plan as string) || "",
+      period: ((search.period as string) || "monthly") as "monthly" | "yearly",
+      brands: (search.brands as string) || "",
+    };
+    const result = search.result as string | undefined;
+    if (result) params.result = result;
+    return params;
+  },
   component: PaymentPage,
 });
 
 function PaymentPage() {
-  const { plan, period, brands } = Route.useSearch();
+  const { plan, period, brands, result } = Route.useSearch();
   const brandIds = brands.split(",").filter(Boolean);
 
   return (
@@ -37,7 +47,7 @@ function PaymentPage() {
         </div>
       }
     >
-      <PaymentContent planKey={plan} period={period} brandIds={brandIds} />
+      <PaymentContent planKey={plan} period={period} brandIds={brandIds} result={result} />
     </Suspense>
   );
 }