test(profile): reputation — bump / slash / admin_slash

[0xdevcollins]

Part of #25 (contract test-coverage push).

profile

How to test

• Reuse the crate's tests/common.rs harness; add tests/reputation.rs + a one-line mod reputation; in tests/mod.rs.
• Template: contracts/profile/src/tests/admin.rs.
• Run cargo test -p boundless-profile, then cargo test --all before the PR.

Acceptance criteria

• New tests/reputation.rs covering every function in scope.
• Happy path + each Error variant + edge cases + auth-rejection (+ idempotency where relevant).
• cargo test --all passes; PR links this issue.

[dev8967]

Implemented in PR #39: #39

[Michaelkingsdev]

Can i work on this issue?