Fix admin authorization and harden chat requests

src/services/streamEvents.js

@@ -0,0 +1,8 @@
+/** Translate model callbacks to small wire events, including corrective-pass resets. */
+export function createTextStreamEvents(sendEvent) {
+    const emit = (event, target) => (chunk, fullText) => {
+        if (chunk === "" && fullText === "") sendEvent("replace", {target, text: ""});
+        else if (chunk) sendEvent(event, {chunk});
+    };
+    return {onChunk: emit("chunk", "reply"), onThinking: emit("thinking", "thinking")};
+}