feat(frontend): add React chat UI with SSE parsing and source accordion

frontend/index.html

@@ -0,0 +1,16 @@
+<!doctype html>
+<html lang="pt-BR" data-theme="dark">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <meta
+      name="description"
+      content="Pastor Online — acompanhamento pastoral ancorado no texto biblico indexado."
+    />
+    <title>Pastor Online</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/main.tsx"></script>
+  </body>
+</html>