refactor: reorganize directory structure and remove hardcoded paths

Move comfyui and vllm out of models/ directory to top level for better
organization. Replace all hardcoded /workspace paths with relative paths
to make the configuration portable across different environments.

Changes:
- Move models/comfyui/ → comfyui/
- Move models/vllm/ → vllm/
- Remove models/ directory (empty)
- Update arty.yml: replace /workspace with environment variables
- Update supervisord.conf: use relative paths from /workspace/ai
- Update all script references to use new paths
- Maintain TQDM_DISABLE=1 to fix BrokenPipeError

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

comfyui/workflows/upscaling/simple-upscale-production-v1.json

@@ -0,0 +1,182 @@
+{
+  "last_node_id": 6,
+  "nodes": [
+    {
+      "id": 1,
+      "type": "LoadImage",
+      "pos": [
+        50,
+        100
+      ],
+      "widgets_values": [
+        "input_image.png",
+        "image"
+      ],
+      "title": "API Input Image",
+      "flags": {},
+      "order": 0,
+      "mode": 0,
+      "properties": {
+        "Node name for S&R": "LoadImage"
+      },
+      "size": {
+        "0": 350,
+        "1": 100
+      }
+    },
+    {
+      "id": 2,
+      "type": "UpscaleModelLoader",
+      "pos": [
+        50,
+        400
+      ],
+      "widgets_values": [
+        "RealESRGAN_x4.pth"
+      ],
+      "title": "Upscale Model Loader",
+      "flags": {},
+      "order": 1,
+      "mode": 0,
+      "properties": {
+        "Node name for S&R": "UpscaleModelLoader"
+      },
+      "size": {
+        "0": 350,
+        "1": 100
+      }
+    },
+    {
+      "id": 3,
+      "type": "ImageUpscaleWithModel",
+      "pos": [
+        450,
+        100
+      ],
+      "title": "Upscale with Model (4x)",
+      "flags": {},
+      "order": 2,
+      "mode": 0,
+      "properties": {
+        "Node name for S&R": "ImageUpscaleWithModel"
+      },
+      "size": {
+        "0": 315,
+        "1": 100
+      }
+    },
+    {
+      "id": 4,
+      "type": "ImageScale",
+      "pos": [
+        800,
+        100
+      ],
+      "widgets_values": [
+        "lanczos",
+        2
+      ],
+      "title": "Optional Downscale to 2x",
+      "flags": {},
+      "order": 3,
+      "mode": 0,
+      "properties": {
+        "Node name for S&R": "ImageScale"
+      },
+      "size": {
+        "0": 315,
+        "1": 100
+      }
+    },
+    {
+      "id": 5,
+      "type": "PreviewImage",
+      "pos": [
+        1150,
+        100
+      ],
+      "title": "Preview Output",
+      "flags": {},
+      "order": 4,
+      "mode": 0,
+      "properties": {
+        "Node name for S&R": "PreviewImage"
+      },
+      "size": {
+        "0": 315,
+        "1": 100
+      }
+    },
+    {
+      "id": 6,
+      "type": "SaveImage",
+      "pos": [
+        1150,
+        400
+      ],
+      "widgets_values": [
+        "simple_upscale_output"
+      ],
+      "title": "API Image Output",
+      "flags": {},
+      "order": 5,
+      "mode": 0,
+      "properties": {
+        "Node name for S&R": "SaveImage"
+      },
+      "size": {
+        "0": 315,
+        "1": 100
+      }
+    }
+  ],
+  "extra": {
+    "workflow_info": {
+      "name": "Simple Upscale Production",
+      "version": "1.0.0",
+      "description": "Fast, straightforward upscaling using RealESRGAN. No diffusion refinement, optimized for speed.",
+      "category": "upscaling",
+      "tags": [
+        "simple-upscale",
+        "fast",
+        "realesrgan",
+        "production"
+      ],
+      "requirements": {
+        "models": [
+          "RealESRGAN"
+        ],
+        "custom_nodes": [],
+        "vram_min": "8GB"
+      },
+      "parameters": {
+        "input_image": {
+          "node_id": 1,
+          "type": "image",
+          "required": true
+        },
+        "model": {
+          "node_id": 2,
+          "type": "string",
+          "default": "RealESRGAN_x4.pth",
+          "options": [
+            "RealESRGAN_x2.pth",
+            "RealESRGAN_x4.pth"
+          ]
+        },
+        "final_scale": {
+          "node_id": 4,
+          "type": "integer",
+          "default": 2
+        }
+      },
+      "performance": {
+        "avg_generation_time": "5-15 seconds",
+        "vram_usage": "~6-8GB"
+      }
+    }
+  },
+  "version": 0.4,
+  "links": [],
+  "last_link_id": 0
+}