Bake quality-focused default negatives into the static workflows

Open WebUI overwrites node 7's text when the request supplies a
negative_prompt, so the default only takes effect when one isn't
provided — which is the common case for the image-button path since the
chat UI doesn't expose the field. Generic quality terms only (no style
or content restrictions) so the default is safe across SD/SDXL/Flux
swaps and doesn't fight whichever checkpoint is loaded.

The smart_image_gen Tool already had per-style defaults; this only
affects the non-Tool image-gen path.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

workflows/img2img.json

@@ -30,7 +30,7 @@
   "7": {
     "class_type": "CLIPTextEncode",
     "inputs": {
-      "text": "",
+      "text": "lowres, blurry, jpeg artifacts, watermark, text, signature, bad anatomy, extra limbs, missing fingers, deformed, ugly, low quality, worst quality",
       "clip": ["4", 1]
     }
   },

workflows/txt2img.json

@@ -38,7 +38,7 @@
   "7": {
     "class_type": "CLIPTextEncode",
     "inputs": {
-      "text": "",
+      "text": "lowres, blurry, jpeg artifacts, watermark, text, signature, bad anatomy, extra limbs, missing fingers, deformed, ugly, low quality, worst quality",
       "clip": ["4", 1]
     }
   },