Frontend OTel: add switch to disable CDN via meta/flag; disable CDN in Conduit index.html to rely on local shim (no external requests)

Author: Maurice Peters

Abies.Conduit/wwwroot/index.html

@@ -9,6 +9,8 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <!-- Aspire: point browser OTLP exporter to API proxy to avoid CORS -->
     <meta name="otlp-endpoint" content="http://localhost:5179/otlp/v1/traces">
+    <!-- Disable CDN imports for OpenTelemetry; use local shim -->
+    <meta name="otel-cdn" content="off">
     <!-- Local Conduit CSS to avoid CORS errors -->
     <link rel="stylesheet" href="css/main.css" />
     <link href="https://code.ionicframework.com/ionicons/2.0.1/css/ionicons.min.css" rel="stylesheet" type="text/css" crossorigin="anonymous">

Abies/wwwroot/abies.js

@@ -17,6 +17,17 @@ let SpanStatusCode = { OK: 1, ERROR: 2 };
 void (async () => {
   try {
     const otelInit = (async () => {
+      // Allow disabling CDN-based OTel via flag or meta tag
+      const useCdn = (() => {
+        try {
+          if (window.__OTEL_USE_CDN === false) return false;
+          const m = document.querySelector('meta[name="otel-cdn"]');
+          const v = (m && m.getAttribute('content')) || '';
+          if (v && v.toLowerCase() === 'off') return false;
+        } catch {}
+        return true;
+      })();
+      if (!useCdn) throw new Error('OTel CDN disabled');
       // Try to load the OTel API first; if it fails, keep using no-op
       let api;
       try {