Ambassador comms — reward-email + marketing copy review & refine

Pending: operator to sample + refine the ambassador program's user-facing comms via the local `/dev/mail` preview harness, then approve for commit. No sending is wired — this is a copy pass. Reward emails (templates built, NOT dispatched — dispatch is Solo todo #576): - AmbassadorReferralRewardNotification — ambassador earned storage, incl. a cap-reached variant. Preview: /dev/mail/ambassador-reward and /dev/mail/ambassador-reward-cap - ReferredBonusIncreasedNotification — referee milestone bonus bump. Preview: /dev/mail/referred-bonus-increased - Copy lives in app/Notifications/Referrals/*. Edit a ->line() and reload the preview to iterate (server-rendered, no build step). Marketing copy to review/refine: - Share kit (stream title / panel text / chat command) — App\Livewire\Settings\AmbassadorDashboard::shareKit() - Invite landing — resources/views/referrals/landing.blade.php - OBS overlays — resources/views/referrals/overlay.blade.php + overlay-progress.blade.php Flow: operator reviews wording → agent applies requested tweaks → commit copy refinements on the held `main`. Separately, wire the reward-email senders (#576) only if emails are to ship at launch. Preview harness: https://vodmanager.test/dev/mail (local only; blocked in production via app()->isProduction()). Depends on / relates to deploy-readiness brief #146.