fix(webapp): make entitlement cache invalidation best-effort

Cache removal in setPlan should not block or throw after the billing
mutation has already committed. Switch from await to fire-and-forget
with .catch(() => {}) so a Redis failure during cache invalidation
cannot 500 the plan-change response.

Per CodeRabbit review.

Author: ericallam

apps/webapp/app/services/platform.v3.server.ts

@@ -373,7 +373,7 @@ export async function setPlan(
       if (result.accepted) {
         // Invalidate billing cache since plan changed
         opts?.invalidateBillingCache?.(organization.id);
-        await platformCache.entitlement.remove(organization.id);
+        platformCache.entitlement.remove(organization.id).catch(() => {});
         return redirect(newProjectPath(organization, "You're on the Free plan."));
       } else {
         return redirectWithErrorMessage(
@@ -390,13 +390,13 @@ export async function setPlan(
     case "updated_subscription": {
       // Invalidate billing cache since subscription changed
       opts?.invalidateBillingCache?.(organization.id);
-      await platformCache.entitlement.remove(organization.id);
+      platformCache.entitlement.remove(organization.id).catch(() => {});
       return redirectWithSuccessMessage(callerPath, request, "Subscription updated successfully.");
     }
     case "canceled_subscription": {
       // Invalidate billing cache since subscription was canceled
       opts?.invalidateBillingCache?.(organization.id);
-      await platformCache.entitlement.remove(organization.id);
+      platformCache.entitlement.remove(organization.id).catch(() => {});
       return redirectWithSuccessMessage(callerPath, request, "Subscription canceled.");
     }
   }