v0.2: Ocean local BQM integration example and tests

[doomhammerhell]

Problem

Noetheris should make Ocean compatibility inspectable without requiring a D-Wave account. The local path should enrich reports when dimod is installed and degrade honestly when it is absent.

Acceptance Criteria

• Extend the Ocean example to emit a concise local parity report when dimod is available.
• Add tests that pass both with and without Ocean installed.
• Verify BQM vartype, variable count, interaction count, offset, and assignment energy.
• Ensure missing optional dependencies never fail default examples or audit.
• Update README optional dependency text if commands change.

Boundary

This issue covers local dimod.BinaryQuadraticModel construction only. It does not submit to D-Wave cloud services.