feat(contracts): implement fee distribution contract with recipient management

[Yunusabdul38]

• Add fee-distribution contract for collecting and distributing fees among configurable recipients
• Implement basis-point (bps) weighted distribution system with 10,000 bps = 100% total
• Add recipient management with atomic updates ensuring shares always sum to 10,000 bps
• Implement permissionless distribution trigger with admin manual distribution capability
• Add reentrancy guard to prevent re-entrant calls during fee distribution
• Include rounding remainder handling credited to first recipient to prevent dust loss
• Update merchant-vault contract with fee distribution integration and enhanced testing
• Add comprehensive test suite covering initialization, deposits, distribution, and edge cases
• Update workspace Cargo.toml to include fee-distribution and escrow-contract members
• Update Cargo.lock with new contract dependencies
  Zap

Closes: #145
Closes: #146

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[ONEONUORA]

Nice implementation @Yunusabdul38