fix: restore AI Assist to use modelAdapter directly

- Removed intermediate /api/ai-assist call that caused 404 with basePath
- AI Assist now calls modelAdapter.generateAIAssistStream directly
- This fixes the HTTP 404 error on the live site

components/AIAssist.tsx

@@ -18,7 +18,6 @@ import { Input } from "@/components/ui/input";
 import useStore from "@/lib/store";
 import { translations } from "@/lib/i18n/translations";
 import modelAdapter from "@/lib/services/adapter-instance";
-import { safeJsonFetch } from "@/lib/safeJsonFetch";
 
 // --- Types ---
 
@@ -346,42 +345,12 @@ export default function AIAssist() {
         setAIAssistHistory(prev => [...prev, assistantMsg]);
 
         try {
-            // First, get the plan orchestrator prompt from our new API
-            type AiAssistApiResponse = {
-                prompt?: string;
-                step?: string;
-                requestId?: string;
-                success?: boolean;
-                error?: string;
-            };
-
-            const apiResult = await safeJsonFetch<AiAssistApiResponse>("/api/ai-assist", {
-                method: "POST",
-                headers: { "Content-Type": "application/json" },
-                body: JSON.stringify({
-                    request: finalInput,
-                    step: assistStep === "plan" ? "generate" : "plan",
-                    plan: aiPlan
-                }),
-            });
-
-            if (!apiResult.ok) {
-                console.error("AI Assist API failed:", apiResult.error);
-                throw new Error(apiResult.error.message);
-            }
-
-            if (apiResult.data.error) {
-                throw new Error(apiResult.data.error);
-            }
-
-            const prompt = apiResult.data.prompt ?? "";
-
             let accumulated = "";
             let lastParsedPreview: PreviewData | null = null;
 
             const response = await modelAdapter.generateAIAssistStream(
                 {
-                    messages: [...aiAssistHistory, { role: "system", content: prompt } as any],
+                    messages: [...aiAssistHistory, { role: "user" as const, content: finalInput, timestamp: new Date() }],
                     currentAgent,
                     onChunk: (chunk) => {
                         accumulated += chunk;