[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/test/unit/src/Project/ProjectListController.test.mjs

@@ -40,6 +40,7 @@ describe('ProjectListController', function () {
         theme: 'textmate',
         mode: 'none',
       },
+      aiFeatures: { enabled: false },
     }
     ctx.users = {
       'user-1': {