[APP-1805] Analytics tweaks and tracking callbacks (#9861)

src/analytics/metrics/client.ts

@@ -4,6 +4,7 @@ import {Logger} from '#/logger'
 import * as env from '#/env'
 
 type Event<M extends Record<string, any>> = {
+  source: 'app'
   time: number
   event: keyof M
   payload: M[keyof M]
@@ -43,7 +44,8 @@ export class MetricsClient<M extends Record<string, any>> {
   ) {
     this.start()
 
-    const e = {
+    const e: Event<M> = {
+      source: 'app',
       time: Date.now(),
       event,
       payload,

src/analytics/metrics/types.ts

@@ -15,6 +15,14 @@ export type Events = {
     experimentId: string
     variationId: string
   }
+  'feature:viewed': {
+    featureId: string
+    featureResultValue: unknown
+    /** Only available if feature has experiment rules applied */
+    experimentId?: string
+    /** Only available if feature has experiment rules applied */
+    variationId?: string
+  }
 
   'account:loggedIn': {
     logContext: