Fix opencode models dropdown not loading on admin page

The populateOpencodeModelSelect() was called from loadConfigured() which
runs in parallel with loadAvailable() in init(). This caused a race condition
where the dropdown could be populated before state.available was set.

Fixed by moving the populateOpencodeModelSelect() call to after all loaders
complete in init(), ensuring state.available is populated first.

chat/public/admin.js

@@ -1588,7 +1588,6 @@
     state.configured = data.models || []; // Legacy support
     renderOpencodeModels();
     renderPublicModels();
-    populateOpencodeModelSelect();
     const selectedAutoModel = state.planSettings && typeof state.planSettings.freePlanModel === 'string'
       ? state.planSettings.freePlanModel
       : (el.autoModelSelect ? el.autoModelSelect.value : '');
@@ -2546,6 +2545,10 @@
         () => (el.externalTestingConfig ? loadExternalTestingStatus() : null),
       ];
       await Promise.all(loaders.map((fn) => fn()).filter(Boolean));
+      // Populate opencode model select after loadAvailable() has completed
+      if (el.opencodeModelSelect) {
+        populateOpencodeModelSelect();
+      }
       // Always try to load provider limits if not already loaded (needed for backup dropdown)
       if (!state.providerModels || Object.keys(state.providerModels).length === 0) {
         try {