feat(pool): add public getters for admin, invoice_contract, escrow_contract

[Bogunrot]

Linked Issue

Closes #578

Problem Statement (The Bug)

The pool contract stores Admin, InvoiceContract, and EscrowContract addresses in instance storage and has private helpers (Self::admin, Self::invoice_contract, Self::escrow_contract) to read them, but only UsdcAsset is exposed via a public getter (get_usdc_asset). There is no way for an off-chain client, another contract, or a test to read the pool's configured admin/invoice/escrow addresses without inspecting raw storage.

Solution Comparison and Decision

• Option A: Expose raw storage reads — Callers use env.storage().instance().get(&DataKey::Admin) directly. This leaks internal key names and breaks encapsulation.
• Option B: Add thin public getters — Wrap existing private helpers, matching the exact pattern of get_usdc_asset. Consistent, simple, and safe.

Option B was chosen because it follows the established pattern and provides a clean public API.

The Change (Code modifications)

Change	File	Description
New getter	contracts/pool/src/lib.rs	get_admin(env) -> Address
New getter	contracts/pool/src/lib.rs	get_invoice_contract(env) -> Address
New getter	contracts/pool/src/lib.rs	get_escrow_contract(env) -> Address
Tests	contracts/pool/src/test.rs	6 tests: 3 happy-path + 3 uninitialized-panic cases

Compatibility Note (On INTERFACE_VERSION)

No interface version change. This is a purely additive change — three new public read-only entry points are added. No existing interface is modified.

Incidental Fixes

• None.

Testing (Proving it works)

• test_get_admin_returns_correct_address: Verifies the admin address matches the one used in initialize().
• test_get_invoice_contract_returns_correct_address: Verifies the invoice contract address matches the one used in initialize().
• test_get_escrow_contract_returns_correct_address: Verifies the escrow contract address matches the one used in initialize().
• test_get_admin_panics_when_uninitialized: Asserts panic for uninitialized contract.
• test_get_invoice_contract_panics_when_uninitialized: Asserts panic for uninitialized contract.
• test_get_escrow_contract_panics_when_uninitialized: Asserts panic for uninitialized contract.

All 6 new tests pass.

Additional Notes

These getters mirror the existing get_usdc_asset pattern and use the private helpers already present in the contract. No storage key changes are needed.

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[mergekeeper]

Needs changes

Public getters for invoice and escrow contracts call private helpers directly without checking option unwrapping or panicking on uninitialized state, causing test failures on expected panic messages.

• contracts/pool/src/lib.rs:202: get_invoice_contract calls Self::invoice_contract(&env) directly which returns Option instead of unwrapping or panicking when uninitialized, causing the corresponding test to fail.
• contracts/pool/src/lib.rs:224: get_escrow_contract calls Self::escrow_contract(&env) directly which returns Option instead of unwrapping or panicking when uninitialized, causing the corresponding test to fail.

Reviewed commit: 3a113939203540033cd3ede908b51d270871f2c4.

[mergekeeper]

Needs changes

Private helper implementations for invoice and escrow contract getters do not unwrap or handle Option types properly compared to admin and usdc assets.

• contracts/pool/src/lib.rs:206: Self::invoice_contract(&env) returns an Option<Address> (or raw helper return type), but lacks .expect(...) like get_admin and get_usdc_asset, causing a type mismatch or missing panic behavior required by the issue.
• contracts/pool/src/lib.rs:228: Self::escrow_contract(&env) lacks .expect(...) to unwrap the Option and provide an uninitialized panic message, which is tested in test.rs expecting specific panic strings.

Reviewed commit: 458bbbad5e03142dc162558303368e41e56ad046.

[mergekeeper]

Needs changes

Public getters for invoice and escrow contracts call private helpers directly without checking option unwrapping or panicking on uninitialized state, causing test failures on expected panic messages.

• contracts/pool/src/lib.rs:202: get_invoice_contract calls Self::invoice_contract(&env) directly which returns Option instead of unwrapping or panicking when uninitialized, causing the corresponding test to fail.
• contracts/pool/src/lib.rs:224: get_escrow_contract calls Self::escrow_contract(&env) directly which returns Option instead of unwrapping or panicking when uninitialized, causing the corresponding test to fail.

Reviewed commit: 3a113939203540033cd3ede908b51d270871f2c4.

[mergekeeper]

MergeKeeper review

Scope: in scope for linked issue #578.
Verdict: clean

The pull request correctly implements the public getters for admin, invoice contract, and escrow contract along with all required tests and documentation matching the issue requirements.

Reviewed commit: 077f45e331c7f784eb0ff01a20158708ca2f557c.
CI and merge eligibility are checked separately.

[mergekeeper]

Approved

The pull request correctly implements the public getters for admin, invoice contract, and escrow contract along with all required tests and documentation matching the issue requirements.

[mergekeeper]

Merged

Merged with squash.