[Feature] Liquidity Pool (LP) Token Staking & Yield Farming Contract

[AlAfiz]

Description: We need a dedicated Staking contract where LPs can deposit their TradeFlow LP tokens to earn a secondary governance/reward token (FLOW) over time.
Context / Motivation: To bootstrap and retain deep liquidity, we must incentivize early adopters. A robust staking mechanism will lock in Total Value Locked (TVL) and distribute governance tokens fairly based on time and amount staked.
Acceptance Criteria: - [ ] Implement deposit and withdrawal mechanisms for LP tokens using the Soroban Token interface.

• Create a time-based reward distribution math model (e.g., reward per token staked).
• Allow users to harvest their rewards without withdrawing their principal.
• Ensure the contract owner can fund the reward pool and update emission rates.
  Technical Pointers: Look into standard staking math (e.g., Synthetix's rewardPerTokenStored model). Use Env::authorize_as_client() to ensure safe token transfers from the user.

[Menjay7]

Hi! I came across this issue and would love to work on it. I have experience with similar tasks and I'm confident I can investigate, implement a clean solution, and thoroughly test it before submitting a PR. If the issue is still open, I would appreciate it if you could assign it to me. Thank you!

[gloskull]

Hi, I would love to work on this Issue.
I have 4 years of experience delivering solutions for projects like this, covering backend, frontend, full-stack and smart contract development. After carefully reviewing your requirements, I have a clear understanding of the task and am confident in my ability to deliver a clean, efficient, and thoroughly tested solution on time. I prioritize code quality, maintainability, and industry best practices throughout the development process.
My PR will be submitted in under 10hours.

[Alanwiz00]

I'd like to take this on.

I've been working with the TradeFlow-Core codebase and I'm familiar with the patterns already used across the Soroban contracts, particularly in amm_pool and amm_factory (token interfaces, admin controls, and the existing contract structure).

My approach would be to:

• Implement a staking model based on the rewardPerTokenStored pattern, maintaining per-user staking state alongside the global reward accounting (totalStaked, rewardRate, lastUpdateTime, etc.).
• Use the Soroban Token interface for LP token deposits and withdrawals, with Env::authorize_as_client() for secure user-authorized transfers.
• Support reward harvesting independently of withdrawals by updating reward accounting on every state-changing operation.
• Add owner-only functions for funding the reward pool and updating emission rates, following the existing admin patterns used in the repository.
• Include comprehensive tests covering deposits, withdrawals, reward accrual, harvesting, and emission rate updates, following the project's existing testing style.

I'll keep the implementation focused on the scope of the issue while following the established patterns already used throughout the repository.