feat: add database support, conversation sidebar, and improve chat streaming

- Update .gitignore to exclude database files, extensions, and .cursor directory
- Enhance chat streaming API with safe enqueue and close functions to prevent errors
- Integrate ConversationSidebar component into ClientHome for better UI
- Add dependencies like better-sqlite3 and esbuild packages for database functionality

This commit introduces database persistence for conversations, improves error handling in streaming responses, and adds a sidebar for managing chats, enhancing overall app robustness and user experience.

app/api/search/route.ts

@@ -0,0 +1,25 @@
+import { NextRequest, NextResponse } from "next/server";
+import { semanticSearch } from "@/lib/vector-search";
+
+export async function POST(request: NextRequest) {
+  try {
+    const { query, limit = 5 } = await request.json();
+
+    if (!query) {
+      return NextResponse.json(
+        { error: "Query é obrigatória" },
+        { status: 400 }
+      );
+    }
+
+    const results = await semanticSearch(query, limit);
+
+    return NextResponse.json(results);
+  } catch (error) {
+    console.error("Erro na busca semântica:", error);
+    return NextResponse.json(
+      { error: "Erro interno do servidor" },
+      { status: 500 }
+    );
+  }
+}