Add Reserve Fund & Protocol Revenue to Lending Contract

[ONEONUORA]

Component: Contracts (Lending) | Effort: 4-5 days | Priority: MEDIUM

Current State

No reserve fund or protocol revenue mechanism. All interest goes to depositors.

Missing Functions

Reserve fund functions:

• set_reserve_factor() - Set percentage of interest for reserves (admin)
• get_reserve_factor() - Get current reserve factor
• get_reserve_balance() - Get accumulated reserves
• withdraw_reserves() - Withdraw reserves (admin/treasury)
• get_protocol_revenue() - Get total protocol revenue
• allocate_reserves() - Allocate reserves to insurance fund

Why This Matters

• Sustainability: Protocol needs revenue for operations
• Insurance: Reserves can cover bad debt
• Governance: Revenue funds development and grants
• Standard practice: All lending protocols have reserve factor

Current Gap

The calculate_interest() function at line 385 doesn't split interest between depositors and protocol. All interest goes to pool.

Tasks

• Add reserve_factor storage (e.g., 10% = 1000 bp)
• Implement set_reserve_factor() (admin only)
• Add reserve_balance tracking
• Modify interest calculation to split interest
  • Depositor share: interest * (1 - reserve_factor)
  • Protocol share: interest * reserve_factor
• Implement withdraw_reserves() (admin/treasury only)
• Add get_reserve_balance() view
• Implement allocate_reserves() to insurance fund
• Track total protocol revenue
• Add ReserveWithdrawn, ReserveAllocated events
• Add tests for reserve calculations
• Document reserve mechanism

Acceptance Criteria

• Reserve factor configurable
• Interest split correctly
• Reserves accumulate properly
• Admin can withdraw reserves
• Tests validate calculations
• Documentation explains reserve model