Initial commit: VLM-as-judge prompt calibration loop

Qwen3-VL image-similarity judge node, external-prompt receptor node,
agent_bridge CLI, example SDXL workflow, and methodology/agent-loop/
calibration-policy docs.

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

.gitignore

@@ -0,0 +1,8 @@
+__pycache__/
+*.pyc
+output/
+models/
+*.safetensors
+*.gguf
+.DS_Store
+.venv/