feat: add meta hints user marks for metadata heuristic override

Users can now right-click nodes and assign meta hints
(primary_model, primary_sampler, positive_prompt,
negative_prompt) to override the metadata processor's
heuristic inference.

- Store extra_data from the API request so workflow node
  properties (including lm_marker_role) are accessible
  during metadata processing.
- _get_user_marks scans extra_data.extra_pnginfo.workflow
  for meta_* marks, falling back to prompt.original_prompt.
- extract_generation_params checks user marks before
  heuristic inference for sampler, model, and prompts.
- Warn on duplicate marks or invalid marked nodes.

web/comfyui/node_marker.js

@@ -7,12 +7,16 @@ import { app } from "../../scripts/app.js";
 // Roles are stored in ``node.properties.lm_marker_role`` and automatically
 // persist with the workflow JSON.
 //
+// Two categories:
+//   send_* – consumed by the standalone UI's "Send to Workflow" feature
+//   meta_* – consumed by the metadata processor to override heuristic inference
+//
 // The workflow registry reads these markers and makes them available to the
 // standalone UI (e.g. ``sendEmbeddingToWorkflow`` also considers nodes marked
 // as ``send_prompt_target``).
 // =============================================================================
 
-const ROLES = {
+const SEND_ROLES = {
   send_prompt_target: {
     label: "Send Prompt Target",
     emoji: "\uD83D\uDCDD",
@@ -23,6 +27,28 @@ const ROLES = {
   },
 };
 
+const META_ROLES = {
+  meta_primary_model: {
+    label: "Meta hints: Primary Model",
+    emoji: "\uD83D\uDCA1",
+  },
+  meta_primary_sampler: {
+    label: "Meta hints: Primary Sampler",
+    emoji: "\uD83D\uDCA1",
+  },
+  meta_positive_prompt: {
+    label: "Meta hints: Positive Prompt",
+    emoji: "\uD83D\uDCA1",
+  },
+  meta_negative_prompt: {
+    label: "Meta hints: Negative Prompt",
+    emoji: "\uD83D\uDCA1",
+  },
+};
+
+// Flat lookup for setMarker / getMarker / clearMarker
+const ROLES = { ...SEND_ROLES, ...META_ROLES };
+
 // ---- Helpers ----------------------------------------------------------------
 
 function getMarker(node) {
@@ -54,7 +80,7 @@ function clearMarker(node) {
   // Restore original title: prefer stripping emoji from current title
   // (captures user renames after marking), fall back to saved original.
   const cleaned = node.title?.replace(
-    /^(\u2709\uFE0F?|\u2699\uFE0F?|\uD83D\uDCDD|\uD83C\uDF9B\uFE0F?|\uD83D\uDD27)\s*/,
+    /^(\u2709\uFE0F?|\u2699\uFE0F?|\uD83D\uDCDD|\uD83C\uDF9B\uFE0F?|\uD83D\uDD27|\uD83D\uDCA1)\s*/,
     ''
   );
   if (cleaned && cleaned !== node.title) {
@@ -84,16 +110,23 @@ function buildSubmenuOptions(node) {
   const currentRole = getMarker(node);
   const options = [];
 
-  for (const [key, def] of Object.entries(ROLES)) {
-    const isActive = currentRole === key;
-    options.push({
-      content: `${isActive ? "\u2713 " : ""}${def.label}`,
-      disabled: isActive,
-      callback: () => setMarker(node, key),
-    });
-  }
+  const buildGroup = (roles) => {
+    for (const [key, def] of Object.entries(roles)) {
+      const isActive = currentRole === key;
+      options.push({
+        content: `${isActive ? "\u2713 " : ""}${def.label}`,
+        disabled: isActive,
+        callback: () => setMarker(node, key),
+      });
+    }
+  };
+
+  buildGroup(SEND_ROLES);
+  options.push(null);  // separator
+  buildGroup(META_ROLES);
 
   if (currentRole) {
+    options.push(null);  // separator
     options.push({
       content: "Clear marker",
       callback: () => clearMarker(node),