fix: handle pre-init PostHog logout reset

If trackLogout fires before the dynamic posthog-js import resolves,
this.posthog?.reset(true) is a no-op and the reset is never applied
later — leaving a path for identity/session bleed across users on
shared browsers. Defer the reset to the init callback via a flag,
and clear the pre-logout event queue at logout time so events
queued before logout don't surface under the post-logout anonymous
distinct_id.

src/platform/telemetry/providers/cloud/PostHogTelemetryProvider.test.ts

@@ -7,20 +7,25 @@ const hoisted = vi.hoisted(() => {
   const mockInit = vi.fn()
   const mockIdentify = vi.fn()
   const mockPeopleSet = vi.fn()
+  const mockReset = vi.fn()
   const mockOnUserResolved = vi.fn()
+  const mockOnUserLogout = vi.fn()
 
   return {
     mockCapture,
     mockInit,
     mockIdentify,
     mockPeopleSet,
+    mockReset,
     mockOnUserResolved,
+    mockOnUserLogout,
     mockPosthog: {
       default: {
         init: mockInit,
         capture: mockCapture,
         identify: mockIdentify,
-        people: { set: mockPeopleSet }
+        people: { set: mockPeopleSet },
+        reset: mockReset
       }
     }
   }
@@ -36,7 +41,8 @@ vi.mock('vue', async () => {
 
 vi.mock('@/composables/auth/useCurrentUser', () => ({
   useCurrentUser: () => ({
-    onUserResolved: hoisted.mockOnUserResolved
+    onUserResolved: hoisted.mockOnUserResolved,
+    onUserLogout: hoisted.mockOnUserLogout
   })
 }))
 
@@ -236,6 +242,50 @@ describe('PostHogTelemetryProvider', () => {
     })
   })
 
+  describe('logout', () => {
+    it('registers onUserLogout watcher before init', () => {
+      createProvider()
+
+      expect(hoisted.mockOnUserLogout).toHaveBeenCalledOnce()
+    })
+
+    it('calls posthog.reset(true) when the watcher fires', async () => {
+      createProvider()
+      await vi.dynamicImportSettled()
+
+      const callback = hoisted.mockOnUserLogout.mock.calls[0][0]
+      callback()
+
+      expect(hoisted.mockReset).toHaveBeenCalledWith(true)
+    })
+
+    it('resets before flushing events queued after a pre-init logout', async () => {
+      const provider = createProvider()
+      const callback = hoisted.mockOnUserLogout.mock.calls[0][0]
+
+      provider.trackUserLoggedIn()
+      callback()
+      provider.trackAuth({ method: 'google' })
+
+      expect(hoisted.mockReset).not.toHaveBeenCalled()
+
+      await vi.dynamicImportSettled()
+
+      expect(hoisted.mockReset).toHaveBeenCalledWith(true)
+      expect(hoisted.mockCapture).not.toHaveBeenCalledWith(
+        TelemetryEvents.USER_LOGGED_IN,
+        expect.anything()
+      )
+      expect(hoisted.mockCapture).toHaveBeenCalledWith(
+        TelemetryEvents.USER_AUTH_COMPLETED,
+        { method: 'google' }
+      )
+      expect(hoisted.mockReset.mock.invocationCallOrder[0]).toBeLessThan(
+        hoisted.mockCapture.mock.invocationCallOrder[0]
+      )
+    })
+  })
+
   describe('page view', () => {
     it('captures page view with page_name property', async () => {
       const provider = createProvider()

src/platform/telemetry/providers/cloud/PostHogTelemetryProvider.ts

@@ -83,6 +83,7 @@ export class PostHogTelemetryProvider implements TelemetryProvider {
   private posthog: PostHog | null = null
   private eventQueue: QueuedEvent[] = []
   private isInitialized = false
+  private shouldResetOnInit = false
   private lastTriggerSource: ExecutionTriggerSource | undefined
   private disabledEvents = new Set<TelemetryEventName>(DEFAULT_DISABLED_EVENTS)
 
@@ -101,6 +102,17 @@ export class PostHogTelemetryProvider implements TelemetryProvider {
     const apiKey = window.__CONFIG__?.posthog_project_token
     if (apiKey) {
       try {
+        const currentUser = useCurrentUser()
+        currentUser.onUserLogout(() => {
+          if (this.isInitialized && this.posthog) {
+            this.posthog.reset(true)
+            return
+          }
+
+          this.shouldResetOnInit = true
+          this.eventQueue = []
+        })
+
         void import('posthog-js')
           .then((posthogModule) => {
             this.posthog = posthogModule.default
@@ -117,9 +129,13 @@ export class PostHogTelemetryProvider implements TelemetryProvider {
               ...serverConfig
             })
             this.isInitialized = true
+            if (this.shouldResetOnInit) {
+              this.posthog.reset(true)
+              this.shouldResetOnInit = false
+            }
             this.flushEventQueue()
 
-            useCurrentUser().onUserResolved((user) => {
+            currentUser.onUserResolved((user) => {
               if (this.posthog && user.id) {
                 this.posthog.identify(user.id)
                 this.setSubscriptionProperties()