fix: add SSE parsing function to handle server-sent events and message processing

frontend/src/App.tsx

@@ -172,6 +172,32 @@ async function fetchOIDCConfig(): Promise<OIDCConfig> {
   return response.json()
 }
 
+function parseSSE(chunk: string, onMessage: (message: string) => void) {
+  const events = chunk.split(/\n\n+/)
+  for (const event of events) {
+    if (!event.trim()) continue
+    const lines = event.split(/\n/)
+    let data = ''
+    for (const line of lines) {
+      const [field, ...rest] = line.split(':')
+      if (field === 'data') {
+        data += rest.join(':').trim()
+      }
+    }
+    if (data && data !== '[DONE]') {
+      try {
+        const parsed = JSON.parse(data)
+        const text = parsed?.choices?.[0]?.delta?.content
+        if (typeof text === 'string') {
+          onMessage(text)
+        }
+      } catch {
+        onMessage(data)
+      }
+    }
+  }
+}
+
 async function handleRedirectCallback(): Promise<string | null> {
   const params = new URLSearchParams(window.location.search)
   const code = params.get('code')