v2.4 — Character Editor + Image-to-Image Portrait Consistency

Features:
- /edit/{name} route: Character nachträglich bearbeiten
- /api/character/update/{name}: API zum Aktualisieren
- create.html dient als Editor und Creator (mode=edit/create)
- Index-Seite: ✏️ Button pro Character
- Portrait-Vorschau im Editor
- Image-to-Image: Folge-Portraits nutzen bestehendes Bild als Referenz
  - LoadImage → ImageScale → VAEEncode → KSampler (denoise=0.45)
  - Aussehen bleibt konsistent über mehrere Generierungen
  - Fallback auf Text-to-Image wenn kein Referenzbild existiert
- ComfyUI Image Upload via /upload/image API
- Jinja2 if-Expressions für vorausgefüllte Formularfelder

comfyui_integration.py

@@ -158,8 +158,83 @@ def wait_for_image(prompt_id: str, timeout: int = 180) -> str | None:
         time.sleep(3)
     return None
 
+def build_i2i_workflow(prompt: str, negative: str, reference_image_path: str, width: int = 512, height: int = 512, denoise: float = 0.45) -> dict:
+    """Image-to-Image Workflow — nutzt ein Referenzbild für Konsistenz."""
+    return {
+        "3": {
+            "class_type": "KSampler",
+            "inputs": {
+                "seed": int(time.time()) % (2**32),
+                "steps": 25,
+                "cfg": 7.0,
+                "sampler_name": "dpmpp_2m",
+                "scheduler": "karras",
+                "denoise": denoise,
+                "model": ["4", 0],
+                "positive": ["6", 0],
+                "negative": ["7", 0],
+                "latent_image": ["10", 0]
+            }
+        },
+        "4": {
+            "class_type": "CheckpointLoaderSimple",
+            "inputs": {"ckpt_name": "NoobAI-XL-v1.1.safetensors"}
+        },
+        "5": {
+            "class_type": "LoadImage",
+            "inputs": {"image": reference_image_path}
+        },
+        "6": {
+            "class_type": "CLIPTextEncode",
+            "inputs": {
+                "text": prompt,
+                "clip": ["4", 1]
+            }
+        },
+        "7": {
+            "class_type": "CLIPTextEncode",
+            "inputs": {
+                "text": f"lowres, bad anatomy, bad hands, text, error, missing fingers, extra digit, fewer digits, cropped, worst quality, low quality, blurry, deformed, ugly, {negative}",
+                "clip": ["4", 1]
+            }
+        },
+        "8": {
+            "class_type": "VAEDecode",
+            "inputs": {"samples": ["3", 0], "vae": ["4", 2]}
+        },
+        "9": {
+            "class_type": "SaveImage",
+            "inputs": {"filename_prefix": "neonchat_portrait", "images": ["8", 0]}
+        },
+        "10": {
+            "class_type": "VAEEncode",
+            "inputs": {"pixels": ["11", 0], "vae": ["4", 2]}
+        },
+        "11": {
+            "class_type": "ImageScale",
+            "inputs": {
+                "image": ["5", 0],
+                "upscale_method": "bilinear",
+                "width": width,
+                "height": height,
+                "crop": "center"
+            }
+        }
+    }
+
+def upload_image_to_comfy(image_path: str) -> str:
+    """Lädt ein Bild zu ComfyUI hoch und gibt den Dateinamen zurück."""
+    import os
+    filename = os.path.basename(image_path)
+    with open(image_path, "rb") as f:
+        files = {"image": (filename, f, "image/png")}
+        with httpx.Client(timeout=30) as client:
+            resp = client.post(f"{COMFYUI_URL}/upload/image", files=files)
+            data = resp.json()
+            return data.get("name", filename)
+
 def generate_portrait(character_name: str, character: dict, context: str = "") -> str | None:
-    """Generiert ein Profilbild basierend auf dem Character-Aussehen."""
+    """Generiert ein Profilbild. Nutzt Image-to-Image wenn ein Referenzbild existiert."""
     if not is_comfyui_running():
         return None
     
@@ -168,7 +243,21 @@ def generate_portrait(character_name: str, character: dict, context: str = "") -
     prompt = build_prompt_from_appearance(character, context)
     negative = "realistic, 3d, render"
     
-    workflow = build_portrait_workflow(prompt, negative, width=512, height=512)
+    # Check if we have a reference image for consistency
+    safe_name = character_name.lower().replace(" ", "_")
+    ref_image = AVATARS_DIR / f"{safe_name}.png"
+    
+    if ref_image.exists():
+        # Image-to-Image for consistency
+        try:
+            uploaded_name = upload_image_to_comfy(str(ref_image))
+            workflow = build_i2i_workflow(prompt, negative, uploaded_name, 512, 512, denoise=0.45)
+        except Exception as e:
+            print(f"I2I upload failed, falling back to T2I: {e}")
+            workflow = build_portrait_workflow(prompt, negative, 512, 512)
+    else:
+        # First generation — Text-to-Image
+        workflow = build_portrait_workflow(prompt, negative, 512, 512)
     
     try:
         prompt_id = queue_prompt(workflow)
@@ -183,7 +272,6 @@ def generate_portrait(character_name: str, character: dict, context: str = "") -
         if not comfy_output.exists():
             return None
         
-        safe_name = character_name.lower().replace(" ", "_")
         dest = AVATARS_DIR / f"{safe_name}.png"
         shutil.copy2(str(comfy_output), str(dest))