Settlement has no `get_fee_config`-analog exposing the effective fee for a merchant

[therealjhay]

ProblemGovernance has get_fee_config; settlement has no per-merchant "what fee will I pay?" read, so callers must reconstruct the chain manually.

1. No effective-fee query.
2. Callers re-implement resolution.
3. API surface gap.

Solution

• Add get_effective_rule(merchant) read.
• Test.

Acceptance Criteria

• Effective fee queryable.
• cargo test --workspace passes.

Note for Contributors: Write a clear PR description. Show the query test.

[Userally16]

Hello Maintainer,

I'd like to work on issue #579. The goal is to add a get_fee_config-analog to settlement that exposes the effective fee for a merchant, since there's currently no way to query this directly.

I'll add the query function, make sure it reflects the correct effective fee logic, and share the details in my PR description.

Could you assign this to me? I'll follow up if I have questions.

Thanks,
Micheal

[grantfox-oss]

🦊 GrantFox — @Userally16 has been assigned to this issue as part of the Third Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #579)
2. Your PR will be reviewed by the Betta-Pay maintainers

Good luck! Track your progress on GrantFox.