feat(onboarding): skippable avatar with first-match prompt and usage-reason pack picks

Lets new users skip the onboarding avatar step and instead defers the ask
to a lightweight, dismissible prompt shown once after the couple's first
match. Also personalizes the home screen's first pack recommendation using
the usage_reason already collected during onboarding, which now round-trips
through GET /v1/me.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

apps/mobile/src/lib/analytics.ts

@@ -257,6 +257,10 @@ export const Events = {
   // Profile events
   profileUpdated: (fields: string[]) => logEvent("profile_updated", { fields: fields.join(",") }),
   avatarUploaded: () => logEvent("avatar_uploaded"),
+  avatarSkipped: () => logEvent("avatar_skipped"),
+  avatarPromptShown: (source: string) => logEvent("avatar_prompt_shown", { source }),
+  avatarPromptAccepted: (source: string) => logEvent("avatar_prompt_accepted", { source }),
+  avatarPromptDismissed: (source: string) => logEvent("avatar_prompt_dismissed", { source }),
 
   // Notification events
   notificationPermissionGranted: () => logEvent("notification_permission_granted"),