Add 7B validation

[Danny1218]

Run a larger-model validation pass when suitable hardware/model files are available.

Goal:

• Separate small-model behavior from family or scale effects.

Acceptance criteria:

• Use the existing calibrated probe workflow.
• Keep outputs isolated from the frozen Qwen2.5-3B and SmolLM2 artifacts.
• Add claim-checked summary language if the result changes deployment guidance.