fix(notifications,referral): dispatch push notifications, expose referral lifecycle endpoints, scope wallet credit and stats

[NteinPrecious]

Addresses the four issues assigned to this account.

• [Wave 200pts] FIX: NotificationProcessor.handleDispatch queue job is a no-op stub — push notifications are never dispatched #1129: NotificationProcessor.handleDispatch is no longer a no-op. It now dispatches through PushNotificationService (with NotificationQueueModule importing PushModule), so queue jobs reach registered devices.
• [Wave 200pts] FIX: Referral reward flow has no API endpoints — applyCode/qualifyReferral/rewardReferral are unreachable #1130: the referral reward flow is now reachable — added POST apply, POST :id/qualify, and POST :id/reward endpoints alongside the existing generate/stats routes.
• [Wave 200pts] FIX: ReferralService.rewardReferral credits the wallet outside the database transaction #1131: rewardReferral now passes the active transaction manager to wallets.adjustBalance so the wallet credit, reward record, and referral status commit (or roll back) atomically.
• [Wave 200pts] FIX: ReferralService.getStats leaks other users' reward totals when the caller has zero rewarded referrals #1132: getStats scopes the reward query to the caller's own rewarded referral IDs; the previous empty-array where clause matched all reward rows. Empty result sets now yield zero totals instead of leaking other users' rewards.

Closes #1129
Closes #1130
Closes #1131
Closes #1132

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