feat(contract): add transfer_meter_ownership function for meter handover

[Dev-AdeTutu]

Feature Request

Area: Smart Contract
File: contracts/solar_grid/src/lib.rs

Description

Meters are permanently tied to the original owner. There is no way to transfer ownership when a household sells their solar setup or a provider reassigns a meter to a new customer.

Implementation Guide

Add to lib.rs:

pub fn transfer_ownership(env: Env, meter_id: Symbol, new_owner: Address) {
    let key = DataKey::Meter(meter_id);
    let mut meter: Meter = env.storage().persistent().get(&key).expect("meter not found");
    meter.owner.require_auth(); // current owner must sign
    meter.owner = new_owner;
    env.storage().persistent().set(&key, &meter);
}

Ensure the new_owner address is a valid Stellar account before storing.

Definition of Done

• Current owner can transfer ownership by signing the transaction
• New owner address stored correctly
• Old owner can no longer call make_payment without re-auth
• Unit test covers transfer and subsequent payment by new owner
• Unit test verifies unauthorized transfer is rejected

[Delightech28]

@Delightech28 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

I'd like to work on this

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[harunacodes790]

@harunacodes790 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

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[soumen0818]

@soumen0818 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

I would like to work on this issue

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[drips-wave]

Congratulations, @harunacodes790! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

🧑‍💻 @harunacodes790: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

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