fix: Update metrics import in copilot setup verification

Correct the import path for metrics verification from compute_coherence
to compute_global_coherence in the coherence submodule.

Intent: Strengthen verification coherence by using correct module paths.

Operators involved: Coherence (IL) - stabilizing verification step

Co-authored-by: fermga <203334638+fermga@users.noreply.github.com>

Author: Copilot

.github/workflows/copilot-setup-steps.yml

@@ -53,7 +53,7 @@ jobs:
           python -c "import tnfr; print(f'TNFR version: {tnfr.__version__}')"
           # Verify core modules are accessible
           python -c "from tnfr.operators import Emission, Coherence, Resonance; print('✓ Core operators available')"
-          python -c "from tnfr.metrics import compute_coherence; print('✓ Metrics available')"
+          python -c "from tnfr.metrics.coherence import compute_global_coherence; print('✓ Metrics available')"
           # Display Python environment info
           python --version
           pip list | grep -E "(tnfr|pytest|numpy|networkx)"