Upload patch_ming_models.py

<content>"""Patch backend: register the new chat models using the Laguna S 2.1 model-path convention.

Fix NameError: remove stray import_anchor_holder line

Register only the 2 chat-capable models; drop ming-image-0.1-design (image-gen, chat/completions 404) and span-01-lite (absent from OpenRouter catalog)

Fix idempotency bug: guard _available_models insert, assert no duplicate entries

Add backend patch for 4 new models (dots-3-note, qwen3.8-27b, span-01-lite, ming-image-design)