fix(billing): don't show an error when a checkout is superseded

src/platform/workspace/stores/billingOperationStore.test.ts

@@ -1,4 +1,5 @@
-import { setActivePinia, createPinia } from 'pinia'
+import { createTestingPinia } from '@pinia/testing'
+import { setActivePinia } from 'pinia'
 import { beforeEach, describe, expect, it, vi, afterEach } from 'vitest'
 import { ref } from 'vue'
 
@@ -80,7 +81,7 @@ import { useBillingOperationStore } from './billingOperationStore'
 
 describe('billingOperationStore', () => {
   beforeEach(() => {
-    setActivePinia(createPinia())
+    setActivePinia(createTestingPinia({ stubActions: false }))
     vi.clearAllMocks()
     vi.useFakeTimers()
     mockActiveWorkspaceId.value = 'workspace-1'
@@ -438,6 +439,72 @@ describe('billingOperationStore', () => {
       })
     })
 
+    it('stays silent when a checkout was superseded by a new plan choice', async () => {
+      vi.mocked(workspaceApi.getBillingOpStatus).mockResolvedValue({
+        id: 'op-1',
+        status: 'failed',
+        error_message: 'checkout_superseded',
+        started_at: new Date().toISOString()
+      })
+
+      const store = useBillingOperationStore()
+      void store.startOperation('op-1', 'subscription')
+
+      await vi.advanceTimersByTimeAsync(0)
+
+      expect(store.getOperation('op-1')?.status).toBe('failed')
+      expect(mockToastAdd).not.toHaveBeenCalledWith(
+        expect.objectContaining({ severity: 'error' })
+      )
+      expect(mockTrackBillingEvent).toHaveBeenCalledWith(
+        expect.objectContaining({
+          stage: 'failed',
+          billing_op_id: 'op-1',
+          failure_category: 'stale_operation'
+        })
+      )
+    })
+
+    it('categorises both events when a superseded op was a downgrade', async () => {
+      vi.mocked(workspaceApi.getBillingOpStatus).mockResolvedValue({
+        id: 'op-1',
+        status: 'failed',
+        error_message: 'checkout_superseded',
+        started_at: new Date().toISOString()
+      })
+
+      const store = useBillingOperationStore()
+      void store.startOperation('op-1', 'subscription', {
+        downgradeToPersonal: {
+          memberRemovalCount: 2,
+          memberRemovalFailures: 0,
+          targetTier: 'free'
+        }
+      })
+
+      await vi.advanceTimersByTimeAsync(0)
+
+      // Both emissions must agree: a downgrade that was merely replaced is not
+      // an unexplained billing failure in either event stream.
+      expect(mockTrackBillingEvent).toHaveBeenCalledWith(
+        expect.objectContaining({
+          operation: 'operation',
+          stage: 'failed',
+          failure_category: 'stale_operation'
+        })
+      )
+      expect(mockTrackBillingEvent).toHaveBeenCalledWith(
+        expect.objectContaining({
+          operation: 'downgrade_to_personal',
+          stage: 'failed',
+          failure_category: 'stale_operation'
+        })
+      )
+      expect(mockTrackBillingEvent).not.toHaveBeenCalledWith(
+        expect.objectContaining({ failure_category: 'unknown' })
+      )
+    })
+
     it('uses default message when no error_message in response', async () => {
       vi.mocked(workspaceApi.getBillingOpStatus).mockResolvedValue({
         id: 'op-1',

src/platform/workspace/stores/billingOperationStore.ts

@@ -25,6 +25,10 @@ const BACKOFF_MULTIPLIER = 1.5
 const TIMEOUT_MS = 120_000
 const SUBSCRIPTION_ACTION_DISCOVERY_TIMEOUT_MS = 5 * 60_000
 const AUTHENTICATION_TIMEOUT_MS = 23 * 60 * 60_000
+// Failure reason for a checkout the user replaced by picking a different plan
+// mid-flow. The operation is terminal-failed only because it never completed —
+// its replacement is proceeding normally, so there is nothing to report.
+const CHECKOUT_SUPERSEDED_REASON = 'checkout_superseded'
 
 type OperationType = 'subscription' | 'topup' | 'cancel'
 type OperationStatus = 'pending' | 'succeeded' | 'failed' | 'timeout'
@@ -356,6 +360,8 @@ export const useBillingOperationStore = defineStore('billingOperation', () => {
     const operation = operations.value.get(opId)
     if (!operation) return
 
+    const superseded = errorMessage === CHECKOUT_SUPERSEDED_REASON
+    const failureCategory = superseded ? 'stale_operation' : 'unknown'
     const defaultMessage = failureMessage(operation.type)
     const detail =
       operation.type === 'subscription'
@@ -376,7 +382,7 @@ export const useBillingOperationStore = defineStore('billingOperation', () => {
       cycle: operation.cycle,
       checkout_type: operation.checkoutType,
       payment_intent_source: operation.paymentIntentSource,
-      failure_category: 'unknown'
+      failure_category: failureCategory
     })
     if (operation.downgradeToPersonal) {
       telemetry?.trackBillingEvent({
@@ -387,11 +393,11 @@ export const useBillingOperationStore = defineStore('billingOperation', () => {
         member_removal_failures:
           operation.downgradeToPersonal.memberRemovalFailures,
         target_tier: operation.downgradeToPersonal.targetTier,
-        failure_category: 'unknown'
+        failure_category: failureCategory
       })
     }
 
-    if (operation.type !== 'cancel') {
+    if (operation.type !== 'cancel' && !superseded) {
       useToastStore().add({
         severity: 'error',
         summary: defaultMessage,