refactor(billing): drop the seat 410 stop-gap; PR 2 ships in the same release

The readable-copy branch only served the window where the seat-era plans
page was live without PR 2's replacement. PR 1 and PR 2 ship as one release,
so that window is zero: the typed 410 error, the classify branch, and their
tests go, leaving the PR with no seat-API changes at all (auto-provisioning
already fails soft on any create error).

Generated-By: PostHog Code
Task-Id: 1039ea23-9930-44e2-9888-b05cf8b129ec

Author: adboio

packages/api-client/src/posthog-client.ts

@@ -133,14 +133,6 @@ export class SeatPaymentFailedError extends Error {
   }
 }
 
-/** Seat creation/upgrades/reactivation return 410 Gone: seats are retired. */
-export class SeatProductRetiredError extends Error {
-  constructor() {
-    super("PostHog Code seats have been retired");
-    this.name = "SeatProductRetiredError";
-  }
-}
-
 export class SandboxCustomImagesDisabledError extends Error {
   constructor(message?: string) {
     super(message ?? "Custom sandbox images are not enabled");
@@ -4597,9 +4589,6 @@ export class PostHogAPIClient {
     const parsed = this.parseFetcherError(error);
 
     if (parsed) {
-      if (parsed.status === 410) {
-        throw new SeatProductRetiredError();
-      }
       if (
         parsed.status === 400 &&
         typeof parsed.body.redirect_url === "string"

packages/core/src/billing/seatErrors.ts

@@ -8,16 +8,6 @@ export function classifySeatError(error: unknown): ClassifiedSeatError {
     return { error: "An unexpected error occurred", redirectUrl: null };
   }
 
-  // Seats are retired (410 Gone); the seat-era UI that can hit this goes
-  // away at cutover, so readable copy is the only handling.
-  if (error.name === "SeatProductRetiredError") {
-    return {
-      error:
-        "PostHog Code seat plans have been retired — usage is now billed to your organization.",
-      redirectUrl: null,
-    };
-  }
-
   if (error.name === "SeatSubscriptionRequiredError") {
     const redirectUrl =
       "redirectUrl" in error && typeof error.redirectUrl === "string"

packages/core/src/billing/seatService.test.ts

@@ -62,13 +62,6 @@ class SeatPaymentFailedError extends Error {
   }
 }
 
-class SeatProductRetiredError extends Error {
-  constructor() {
-    super("PostHog Code seats have been retired");
-    this.name = "SeatProductRetiredError";
-  }
-}
-
 beforeEach(() => {
   vi.clearAllMocks();
 });
@@ -285,27 +278,3 @@ describe("error classification", () => {
     expect(result.error).toBe("Card declined");
   });
 });
-
-// The seat API 410s creation/upgrades/reactivation once Code seats are
-// retired in favor of usage-based billing (reads keep working).
-describe("seat product retired (410 Gone)", () => {
-  it("treats a retired auto-provision as seatless instead of erroring", async () => {
-    const client = makeClient({
-      createSeat: vi.fn().mockRejectedValue(new SeatProductRetiredError()),
-    });
-    const result = await new SeatService(client, logger).fetchSeat({
-      autoProvision: true,
-    });
-    expect(result.seat).toBeNull();
-    expect(result.error).toBeNull();
-  });
-
-  it("surfaces retirement as a clear error on an explicit upgrade", async () => {
-    const client = makeClient({
-      createSeat: vi.fn().mockRejectedValue(new SeatProductRetiredError()),
-    });
-    const result = await new SeatService(client, logger).upgradeToPro();
-    expect(result.error).toContain("retired");
-    expect(result.redirectUrl).toBeNull();
-  });
-});