refactor: remove sampling logic for small nightly cohort

- Remove sampleRate config option, getUserSamplingId, isUserInSample
- Simplifies eligibility to ~2k nightly users without random sampling
- Addresses coderabbitai review: hash edge case bug, YAGNI for cohort size
- Document featureId must remain static after initialization

src/platform/surveys/useSurveyEligibility.test.ts

@@ -2,7 +2,6 @@ import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 
 const SURVEY_STATE_KEY = 'Comfy.SurveyState'
 const FEATURE_USAGE_KEY = 'Comfy.FeatureUsage'
-const USER_SAMPLING_ID_KEY = 'Comfy.SurveyUserId'
 
 const mockIsNightly = vi.hoisted(() => ({ value: true }))
 const mockIsCloud = vi.hoisted(() => ({ value: false }))
@@ -263,62 +262,6 @@ describe('useSurveyEligibility', () => {
     })
   })
 
-  describe('sampling', () => {
-    it('creates stable user sampling ID', async () => {
-      setFeatureUsage('test-feature', 5)
-
-      const { useSurveyEligibility } = await import('./useSurveyEligibility')
-      const { isEligible } = useSurveyEligibility({
-        ...defaultConfig,
-        sampleRate: 0.5
-      })
-
-      // Access isEligible to trigger sampling check
-      void isEligible.value
-
-      const userId = localStorage.getItem(USER_SAMPLING_ID_KEY)
-      expect(userId).toBeTruthy()
-      expect(userId).toMatch(
-        /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/
-      )
-    })
-
-    it('reuses existing user sampling ID', async () => {
-      const existingId = '12345678-1234-1234-1234-123456789012'
-      localStorage.setItem(USER_SAMPLING_ID_KEY, existingId)
-      setFeatureUsage('test-feature', 5)
-
-      const { useSurveyEligibility } = await import('./useSurveyEligibility')
-      useSurveyEligibility({ ...defaultConfig, sampleRate: 0.5 })
-
-      expect(localStorage.getItem(USER_SAMPLING_ID_KEY)).toBe(existingId)
-    })
-
-    it('sample rate of 0 excludes all users', async () => {
-      setFeatureUsage('test-feature', 5)
-
-      const { useSurveyEligibility } = await import('./useSurveyEligibility')
-      const { isEligible } = useSurveyEligibility({
-        ...defaultConfig,
-        sampleRate: 0
-      })
-
-      expect(isEligible.value).toBe(false)
-    })
-
-    it('sample rate of 1 includes all users', async () => {
-      setFeatureUsage('test-feature', 5)
-
-      const { useSurveyEligibility } = await import('./useSurveyEligibility')
-      const { isEligible } = useSurveyEligibility({
-        ...defaultConfig,
-        sampleRate: 1
-      })
-
-      expect(isEligible.value).toBe(true)
-    })
-  })
-
   describe('config values', () => {
     it('exposes delayMs from config', async () => {
       const { useSurveyEligibility } = await import('./useSurveyEligibility')

src/platform/surveys/useSurveyEligibility.ts

@@ -8,11 +8,11 @@ import { useFeatureUsageTracker } from './useFeatureUsageTracker'
 
 /** @public */
 export interface FeatureSurveyConfig {
+  /** Feature identifier. Must remain static after initialization. */
   featureId: string
   typeformId: string
   triggerThreshold?: number
   delayMs?: number
-  sampleRate?: number
   enabled?: boolean
 }
 
@@ -26,7 +26,6 @@ const STORAGE_KEY = 'Comfy.SurveyState'
 const GLOBAL_COOLDOWN_MS = 14 * 24 * 60 * 60 * 1000 // 14 days
 const DEFAULT_THRESHOLD = 3
 const DEFAULT_DELAY_MS = 5000
-const DEFAULT_SAMPLE_RATE = 1
 
 function getStorageState() {
   return useStorage<SurveyState>(STORAGE_KEY, {
@@ -50,9 +49,6 @@ export function useSurveyEligibility(
   const delayMs = computed(
     () => resolvedConfig.value.delayMs ?? DEFAULT_DELAY_MS
   )
-  const sampleRate = computed(
-    () => resolvedConfig.value.sampleRate ?? DEFAULT_SAMPLE_RATE
-  )
   const enabled = computed(() => resolvedConfig.value.enabled ?? true)
 
   const isNightlyLocalhost = computed(() => isNightly && !isCloud && !isDesktop)
@@ -78,11 +74,6 @@ export function useSurveyEligibility(
     if (isInGlobalCooldown.value) return false
     if (hasOptedOut.value) return false
 
-    if (sampleRate.value < 1) {
-      const userId = getUserSamplingId()
-      if (!isUserInSample(userId, sampleRate.value)) return false
-    }
-
     return true
   })
 
@@ -116,25 +107,3 @@ export function useSurveyEligibility(
     resetState
   }
 }
-
-const USER_SAMPLING_ID_KEY = 'Comfy.SurveyUserId'
-
-function getUserSamplingId(): string {
-  let id = localStorage.getItem(USER_SAMPLING_ID_KEY)
-  if (!id) {
-    id = crypto.randomUUID()
-    localStorage.setItem(USER_SAMPLING_ID_KEY, id)
-  }
-  return id
-}
-
-function isUserInSample(userId: string, sampleRate: number): boolean {
-  let hash = 0
-  for (let i = 0; i < userId.length; i++) {
-    const char = userId.charCodeAt(i)
-    hash = (hash << 5) - hash + char
-    hash = hash & hash
-  }
-  const normalized = Math.abs(hash) / 0x7fffffff
-  return normalized < sampleRate
-}