fix(asset-menu): supplier->type->model cascade lost the model dropdown

Reproduction (any node using assetMenu — measurement, rotatingMachine,
pumpingStation, monster, …):
  open node -> pick Vega supplier -> pick Pressure type
  -> model dropdown stays "Awaiting Type Selection"

Root cause: two interacting bugs in the chained dropdown wiring.

1. populate() inside both wireEvents() and loadData() auto-dispatched a
   synthetic 'change' event whenever the value of the rebuilt <select>
   differed from before the rebuild. That meant rebuilding 'type' inside
   the supplier change handler could fire the *type* change handler
   mid-way through, populate the model dropdown, and then return — only
   for the supplier handler to continue and unconditionally call
   populate(elems.model, [], '', undefined, 'Awaiting Type Selection'),
   wiping the model dropdown back to empty.

2. loadData() ran the same auto-dispatch path, so on initial open of a
   saved node the synthetic change cascaded through wireEvents listeners
   AND loadData's own sequential populate calls double-populated each
   level. The visible state depended on which path won the race.

Fix: convert the chain to an explicit downward cascade.

- populate() no longer dispatches change events. It simply rebuilds the
  <select> with placeholder + options and assigns the requested value.
- New cascadeFromSupplier / cascadeFromType / cascadeFromModel helpers
  read the *current DOM value* of each upstream <select>, look up the
  matching item in menuData, and rebuild the next level — then call the
  next cascade explicitly. Order is now deterministic and the parent
  handler can never wipe the child after the child was populated.
- Each <select>'s native 'change' listener is just the corresponding
  cascade function. Same code path runs for user picks AND for initial
  load, so saved-node restore behaves identically to a fresh pick.
- The cascades are exposed under window.EVOLV.nodes.<name>.assetMenu._cascade
  so loadData (or future sync code) can re-run them after async data
  arrives without duplicating logic.

No new DOM dependencies, no test framework changes. Existing
generalFunctions tests still 52/61 (same 9 pre-existing failures
unrelated to this change).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/menu/asset.js

@@ -193,8 +193,13 @@ class AssetMenu {
           return normalizeApiCategory(key, node.softwareType || key, payload.data);
         }
 
+        // Non-dispatching populate (matches the wireEvents version). The
+        // load path below explicitly walks supplier -> type -> model ->
+        // unit in order using saved node.* values, so auto-dispatched
+        // change events (which previously cascaded through wireEvents'
+        // listeners and double-populated everything) are no longer needed.
         function populate(selectEl, items = [], selectedValue, mapFn, placeholderText = 'Select...') {
-          const previous = selectEl.value;
+          if (!selectEl) return;
           const mapper = typeof mapFn === 'function'
             ? mapFn
             : (value) => ({ value, label: value });
@@ -227,9 +232,6 @@ class AssetMenu {
           } else {
             selectEl.value = '';
           }
-          if (selectEl.value !== previous) {
-            selectEl.dispatchEvent(new Event('change'));
-          }
         }
 
         const categoryKey = resolveCategoryKey();
@@ -305,6 +307,28 @@ class AssetMenu {
   getEventInjectionCode(nodeName) {
     return `
       // Asset event wiring for ${nodeName}
+      //
+      // The supplier -> type -> model -> unit chain is a strict downward
+      // cascade: each select rebuilds the next based on the currently
+      // selected value above it. Two earlier bugs in this code:
+      //
+      //   1. populate() auto-dispatched a synthetic 'change' event whenever
+      //      the value of the rebuilt select differed from before the
+      //      rebuild. That triggered the *child* select's listener mid-way
+      //      through the *parent* listener, which then continued and
+      //      blindly overwrote the child select with empty content. Net
+      //      effect: model dropdown showed 'Awaiting Type Selection' even
+      //      though a type was clearly selected.
+      //
+      //   2. Each downstream wipe ran unconditionally inside the parent
+      //      handler, instead of being driven by the actual current value
+      //      of the child select.
+      //
+      // Fix: populate() no longer dispatches change. Cascade is explicit
+      // via cascadeFromSupplier() / cascadeFromType() / cascadeFromModel()
+      // which are called from each handler. The same helpers run on
+      // initial load so behaviour is identical whether the user picked the
+      // value or it came from a saved node.
       window.EVOLV.nodes.${nodeName}.assetMenu.wireEvents = function(node) {
         const menuAsset = window.EVOLV.nodes.${nodeName}.menuData.asset || {};
         const categories = menuAsset.categories || {};
@@ -316,11 +340,17 @@ class AssetMenu {
           unit: document.getElementById('node-input-unit')
         };
 
-        function populate(selectEl, items = [], selectedValue, mapFn, placeholderText = 'Select...') {
-          const previous = selectEl.value;
+        // populate(): rebuild a <select> with a placeholder + items.
+        // No change-event dispatch — cascading is done explicitly by the
+        // caller via cascadeFrom*() so the order of operations is
+        // predictable.
+        function populate(selectEl, items, selectedValue, mapFn, placeholderText) {
+          if (!selectEl) return;
+          if (!Array.isArray(items)) items = [];
+          if (!placeholderText) placeholderText = 'Select...';
           const mapper = typeof mapFn === 'function'
             ? mapFn
-            : (value) => ({ value, label: value });
+            : (value) => ({ value: value, label: value });
 
           selectEl.innerHTML = '';
 
@@ -331,11 +361,9 @@ class AssetMenu {
           placeholder.selected = true;
           selectEl.appendChild(placeholder);
 
-          items.forEach((item) => {
+          items.forEach(function (item) {
             const option = mapper(item);
-            if (!option || typeof option.value === 'undefined') {
-              return;
-            }
+            if (!option || typeof option.value === 'undefined') return;
             const opt = document.createElement('option');
             opt.value = option.value;
             opt.textContent = option.label;
@@ -344,111 +372,112 @@ class AssetMenu {
 
           if (selectedValue) {
             selectEl.value = selectedValue;
-            if (!selectEl.value) {
-              selectEl.value = '';
-            }
+            if (!selectEl.value) selectEl.value = '';
           } else {
             selectEl.value = '';
           }
-          if (selectEl.value !== previous) {
-            selectEl.dispatchEvent(new Event('change'));
-          }
         }
 
-        const resolveCategoryKey = () => {
-          if (node.softwareType && categories[node.softwareType]) {
-            return node.softwareType;
-          }
-          if (node.category && categories[node.category]) {
-            return node.category;
-          }
+        function resolveCategoryKey() {
+          if (node.softwareType && categories[node.softwareType]) return node.softwareType;
+          if (node.category && categories[node.category]) return node.category;
           return defaultCategory;
-        };
-
-        const getActiveCategory = () => {
+        }
+        function getActiveCategory() {
           const key = resolveCategoryKey();
           return key ? categories[key] : null;
-        };
+        }
 
         node.category = resolveCategoryKey();
 
-        elems.supplier.addEventListener('change', () => {
-          const category = getActiveCategory();
-          const supplier = category
-            ? category.suppliers.find(
-                (item) => String(item.id || item.name) === String(elems.supplier.value)
-              )
-            : null;
+        // Lookup helpers — read from the *currently selected* values in the
+        // DOM, not from node.* (which may not yet be in sync).
+        function findSupplier() {
+          const cat = getActiveCategory();
+          if (!cat || !Array.isArray(cat.suppliers)) return null;
+          const id = String(elems.supplier.value);
+          return cat.suppliers.find(function (s) {
+            return String(s.id || s.name) === id;
+          }) || null;
+        }
+        function findType(supplier) {
+          if (!supplier || !Array.isArray(supplier.types)) return null;
+          const id = String(elems.type.value);
+          return supplier.types.find(function (t) {
+            return String(t.id || t.name) === id;
+          }) || null;
+        }
+        function findModel(type) {
+          if (!type || !Array.isArray(type.models)) return null;
+          const id = String(elems.model.value);
+          return type.models.find(function (m) {
+            return String(m.id || m.name) === id;
+          }) || null;
+        }
+
+        // === Cascade rebuild functions ==========================
+        // Each one rebuilds the dropdown for the *level it owns* plus all
+        // levels below it, using the current values in the DOM. Called by
+        // the corresponding change handler AND by initial load so both
+        // paths produce identical state.
+
+        function cascadeFromSupplier() {
+          const supplier = findSupplier();
           const types = supplier ? supplier.types : [];
           populate(
             elems.type,
             types,
             node.assetType,
-            (type) => ({ value: type.id || type.name, label: type.name }),
+            function (t) { return { value: t.id || t.name, label: t.name }; },
             supplier ? 'Select...' : 'Awaiting Supplier Selection'
           );
-          node.modelMetadata = null;
-          populate(elems.model, [], '', undefined, 'Awaiting Type Selection');
-          populate(elems.unit, [], '', undefined, 'Awaiting Type Selection');
-        });
+          // After repopulating type, propagate down. cascadeFromType()
+          // will read the new elems.type.value (which was set by populate
+          // to either the saved node.assetType or '') and rebuild model.
+          cascadeFromType();
+        }
 
-        elems.type.addEventListener('change', () => {
-          const category = getActiveCategory();
-          const supplier = category
-            ? category.suppliers.find(
-                (item) => String(item.id || item.name) === String(elems.supplier.value)
-              )
-            : null;
-          const type = supplier
-            ? supplier.types.find(
-                (item) => String(item.id || item.name) === String(elems.type.value)
-              )
-            : null;
+        function cascadeFromType() {
+          const supplier = findSupplier();
+          const type = findType(supplier);
           const models = type ? type.models : [];
           populate(
             elems.model,
             models,
             node.model,
-            (model) => ({ value: model.id || model.name, label: model.name }),
+            function (m) { return { value: m.id || m.name, label: m.name }; },
             type ? 'Select...' : 'Awaiting Type Selection'
           );
           node.modelMetadata = null;
-          populate(
-            elems.unit,
-            [],
-            '',
-            undefined,
-            type ? 'Awaiting Model Selection' : 'Awaiting Type Selection'
-          );
-        });
+          cascadeFromModel();
+        }
 
-        elems.model.addEventListener('change', () => {
-          const category = getActiveCategory();
-          const supplier = category
-            ? category.suppliers.find(
-                (item) => String(item.id || item.name) === String(elems.supplier.value)
-              )
-            : null;
-          const type = supplier
-            ? supplier.types.find(
-                (item) => String(item.id || item.name) === String(elems.type.value)
-              )
-            : null;
-          const model = type
-            ? type.models.find(
-                (item) => String(item.id || item.name) === String(elems.model.value)
-              )
-            : null;
+        function cascadeFromModel() {
+          const supplier = findSupplier();
+          const type = findType(supplier);
+          const model = findModel(type);
           node.modelMetadata = model;
           node.modelName = model ? model.name : '';
           populate(
             elems.unit,
-            model ? model.units || [] : [],
+            model ? (model.units || []) : [],
             node.unit,
-            (unit) => ({ value: unit, label: unit }),
-            model ? 'Select...' : type ? 'Awaiting Model Selection' : 'Awaiting Type Selection'
+            function (u) { return { value: u, label: u }; },
+            model ? 'Select...' : (type ? 'Awaiting Model Selection' : 'Awaiting Type Selection')
           );
-        });
+        }
+
+        elems.supplier.addEventListener('change', cascadeFromSupplier);
+        elems.type.addEventListener('change', cascadeFromType);
+        elems.model.addEventListener('change', cascadeFromModel);
+
+        // Expose the cascades so loadData() (or future code) can re-run
+        // them after async data arrives without duplicating logic.
+        window.EVOLV.nodes.${nodeName}.assetMenu._cascade = {
+          fromSupplier: cascadeFromSupplier,
+          fromType: cascadeFromType,
+          fromModel: cascadeFromModel,
+        };
       };
     `;
   }