Trim dead inputs: drop fp16 precision and prompt_used

fp16 offers nothing over bf16 for these models (removed from the quant dropdown;
loader still tolerant if passed). prompt_used was metadata-only — removed from the
node inputs, report payload/markdown, the bridge, and the example workflows.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

agent_bridge.py

@@ -67,7 +67,6 @@ def _inject(graph: dict, prompt: str, negative: str, seed: int, run_tag: str, mo
         elif ctype == JUDGE_CLASS:
             inputs["mode"] = mode
             inputs["run_tag"] = run_tag
-            inputs["prompt_used"] = prompt
             if reference_description:
                 inputs["reference_description"] = reference_description
             if profile: