demo: icon recipe pipeline + role-aware portraits + ComfyUI negative-prompt override

Adds two single-source-of-truth recipe files that drive both the
hot-path render server and the offline pre-render scripts:

- role_scenes.ts: per-role-band scene clauses (clothing + backdrop).
  Forklift operators look like forklift operators instead of
  collapsing to interchangeable studio shots. SCENES_VERSION mixes
  into the headshot cache key so a coordinator tweak refreshes every
  matching face on next view.
- icon_recipes.ts: cert / role-prop / status / hazard / empty icons
  with deterministic per-recipe seeds + fuzzy text resolver.
  ICONS_VERSION suffix on the cached file means edits don't
  overwrite in place — misfires are recoverable.

Routes (mcp-server/index.ts):
- GET /headshots/_scenes — exposes SCENES + version to the
  pre-render script so prompts don't drift between batch and hot-path.
- GET /icons/_recipes — same idea for icons.
- GET /icons/cert?text=... — resolves free-text cert names to a
  recipe and 302s to the rendered icon. 404 (not 500) when no recipe
  matches so the front-end can hang `onerror="this.remove()"`.
- GET /icons/render/{category}/{slug} — cache-or-render at 256² (8
  steps) for crisper edges than 512² when downsampled to 14px.

ComfyUI portrait support (scripts/serve_imagegen.py):
The editorial workflow had `human, person, face` baked into its
negative prompt — actively sabotaging portraits. _comfyui_generate
now accepts negative_prompt/cfg/sampler/scheduler overrides, and
those mix into the cache key so portrait calls don't collapse into
hero-shot cache hits.

scripts/staffing/render_role_pool.py: pre-renders the role-aware
face pool by reading SCENES from /headshots/_scenes — single source
of truth verified at run time.

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

scripts/serve_imagegen.py

@@ -46,8 +46,15 @@ def _cache_put(key, img_bytes):
     (CACHE_DIR / f"{key}.webp").write_bytes(img_bytes)
 
 
-def _comfyui_generate(prompt, width=1024, height=512, steps=8, seed=None):
-    """Submit workflow to ComfyUI and wait for result."""
+def _comfyui_generate(prompt, width=1024, height=512, steps=8, seed=None,
+                      negative_prompt=None, cfg=None, sampler=None, scheduler=None):
+    """Submit workflow to ComfyUI and wait for result.
+
+    Optional overrides — when provided, replace the workflow's defaults.
+    The workflow template at editorial_hero.json was tuned for product
+    hero shots with a "no humans" negative prompt; portrait callers MUST
+    pass `negative_prompt` to avoid the model fighting them on faces.
+    """
     # Load workflow template
     with open(WORKFLOW_PATH) as f:
         workflow = json.load(f)
@@ -57,9 +64,21 @@ def _comfyui_generate(prompt, width=1024, height=512, steps=8, seed=None):
         seed = random.randint(0, 2**32)
     workflow["3"]["inputs"]["seed"] = seed
     workflow["3"]["inputs"]["steps"] = steps
+    if cfg is not None:
+        workflow["3"]["inputs"]["cfg"] = cfg
+    if sampler:
+        workflow["3"]["inputs"]["sampler_name"] = sampler
+    if scheduler:
+        workflow["3"]["inputs"]["scheduler"] = scheduler
     workflow["5"]["inputs"]["width"] = width
     workflow["5"]["inputs"]["height"] = height
     workflow["6"]["inputs"]["text"] = prompt
+    # Node 7 is the negative-prompt CLIPTextEncode. The default is tuned
+    # for product hero shots and contains "human, person, face, hand,
+    # fingers, realistic photo of people" — actively sabotaging any
+    # portrait render. Always overwrite when negative_prompt is given.
+    if negative_prompt is not None:
+        workflow["7"]["inputs"]["text"] = negative_prompt
 
     # Submit to ComfyUI
     payload = json.dumps({"prompt": workflow}).encode()
@@ -183,10 +202,20 @@ class ImageHandler(BaseHTTPRequestHandler):
         height = min(max(int(body.get("height", 720)), 256), 1080)
         steps = min(max(int(body.get("steps", 50)), 1), 80)
         seed = body.get("seed")
+        # Portrait-friendly overrides — None means "use workflow default".
+        # negative_prompt MUST be passed by portrait callers to avoid
+        # the workflow's "no humans" baked-in negative.
+        negative_prompt = body.get("negative_prompt")
+        cfg = body.get("cfg")
+        sampler = body.get("sampler")
+        scheduler = body.get("scheduler")
 
-        # Cache check — seed is part of the key so per-worker requests
-        # don't collapse to a single cached portrait.
-        key = _cache_key(prompt, width, height, steps, seed)
+        # Cache check — seed + negative + cfg are part of the key so per-
+        # worker / per-config requests don't collapse to one cached image.
+        key = _cache_key(
+            f"{prompt}||neg={negative_prompt or ''}||cfg={cfg or ''}",
+            width, height, steps, seed,
+        )
         cached = _cache_get(key)
         if cached:
             self._json(200, {"image": cached, "format": "webp", "width": width, "height": height,
@@ -199,7 +228,11 @@ class ImageHandler(BaseHTTPRequestHandler):
         try:
             comfy_check = urllib.request.urlopen(f"{COMFYUI_URL}/system_stats", timeout=3)
             if comfy_check.status == 200:
-                img_bytes, seed = _comfyui_generate(prompt, width, height, steps, seed)
+                img_bytes, seed = _comfyui_generate(
+                    prompt, width, height, steps, seed,
+                    negative_prompt=negative_prompt, cfg=cfg,
+                    sampler=sampler, scheduler=scheduler,
+                )
                 backend = "comfyui"
         except:
             pass