feat: revenue_pool pause guardian

[Jerry-Tekh]

Summary

• Add an admin-managed pause_guardian role to callora-revenue-pool
• Allow the guardian to call pause only; unpause, distribution, admin rotation, cap updates, guardian management, and upgrades remain admin-only
• Add guardian set/clear events, focused tests, and interface/access-control documentation

Tests

• cargo test -p callora-revenue-pool (83 passed)
• cargo clippy -p callora-revenue-pool --all-targets --all-features -- -D warnings
• rustfmt --check contracts/revenue_pool/src/lib.rs contracts/revenue_pool/src/events.rs contracts/revenue_pool/src/test.rs contracts/revenue_pool/src/test_invariant.rs
• python3 -m json.tool docs/interfaces/revenue_pool.json
• git diff --check

Notes

• cargo test --workspace currently fails outside this change before completing because existing settlement/vault tests are out of sync with their contract APIs, including stale withdraw_developer_balance call arity in settlement tests and duplicate/missing revenue-pool setter tests in vault tests.
• cargo fmt --all -- --check reports formatting diffs in existing non-revenue-pool files; the touched revenue-pool Rust files pass rustfmt --check.

Closes #530

[greatest0fallt1me]

Merged via direct push to main (admin)

[Jerry-Tekh]

Summary

• Add an admin-managed pause_guardian role to callora-revenue-pool
• Allow the guardian to call pause only; unpause, distribution, admin rotation, cap updates, guardian management, and upgrades remain admin-
  only
• Add guardian set/clear events, focused tests, and interface/access-control documentation

Tests

• cargo test -p callora-revenue-pool (83 passed)
• cargo clippy -p callora-revenue-pool --all-targets --all-features -- -D warnings
• rustfmt --check contracts/revenue_pool/src/lib.rs contracts/revenue_pool/src/events.rs contracts/revenue_pool/src/test.rs contracts/ revenue_pool/src/test_invariant.rs
• python3 -m json.tool docs/interfaces/revenue_pool.json
• git diff --check

Notes

• cargo test --workspace currently fails outside this change because existing settlement/vault tests are out of sync with their contract APIs.
• cargo fmt --all -- --check reports formatting diffs in existing non-revenue-pool files; touched revenue-pool Rust files pass rustfmt --check.

Closes #530