[Web] Enable Quota System for AI Features (#31544)

* feat: migrate from aiErrorAssist naming for disabling AI features to aiFeatures.enabled to avoid confusion

feat: keep aiErrorAssistant as setting on user object until migration is run

* feat: migrate writefull.enabled unset to instead use promotionSet false

* feat: updating to use quota based system for AI usage

* feat: hide relevant sections of quota system behind split test

* feat: ship onAiFreeTrial instead of free quota amount to project meta

* fix: renaming splitTestEnabledForUser to featureFlagEnabledForUser

* fix: v1_personal should have free trial amount of ai quota

* fix: onAiFreeTrial in projectController should account for anonymous users with no features

* feat: fixing marketing exports for ai quotas

* feat: update features epoch

* feat: move to quota tiers, and map tier to numeric allowance within rateLimiters

GitOrigin-RevId: 17763447965aae5777053b783d2601517bfe6b12

services/web/types/user.ts

@@ -10,6 +10,7 @@ export type UserId = Brand<string, 'UserId'>
 
 export type Features = {
   aiErrorAssistant?: boolean
+  aiUsageQuota?: string
   collaborators?: number
   compileGroup?: 'standard' | 'priority'
   compileTimeout?: number