feat: validate commitment existence in transformation entrypoints

[Glam26]

I have implemented the cross-contract commitment validation in the
commitment_transformation contract and ensured that the entire test suite is
passing.

Changes Implemented

1. Cross-Contract Validation: Updated the load_commitment helper in
   contracts/commitment_transformation/src/lib.rs to verify that a commitment
   fetched from commitment_core has a status of "active". If the status is
   different, it now fails with TransformationError::InvalidState.
2. Environment & Compilation Fixes:
   • Fixed a corrupted Cargo.lock (duplicate version-system entries).
   • Updated contracts/shared_utils/src/lib.rs to re-export emit_error_event
     and Validation, resolving import errors.
   • Fixed duplicate imports and missing module declarations for tests and
     mocks in commitment_transformation.
3. Mock Core Stabilization:
   • Updated MockCommitmentCore to return a full CoreCommitment equivalent,
     ensuring compatibility with the contract's expected data types.
   • Implemented deterministic ownership in the mock core to satisfy
     existing test assertions.
   • Registered the mock core contract in both tests.rs and
     invalid_state_tests.rs setup helpers.
4. Verification:
   • Added a new test case test_create_tranches_with_expired_commitment in
     invalid_state_tests.rs to verify that transformations on non-active
     commitments are rejected.
   • Confirmed that all 64 tests in the commitment_transformation crate pass
     successfully.
5. Documentation:
   • Updated docs/COMMITMENT_TRANSFORMATION_AUTHORIZATION.md to include
     status checks in the cross-contract call notes.
   • Updated docs/RISK_TRANCHES.md to explicitly list the "active" status
     requirement for tranche creation.

Commit Summary
I have committed the changes to the feature/transformation-commitment-check
branch with the message:
feat: validate commitment existence in transformation entrypoints

All tests can be verified by running:
1 cargo test -p commitment_transformation --lib

closes #474