feat: PromptArch v2.1 - Agentic AI Assist 3-Step Flow + Slides Enhancements

- Implemented Plan -> Approve -> Generate workflow in AIAssist
- Added Plan Review Card with architecture/tech stack preview
- Added Reveal.js Markdown export to SlidesGenerator
- Created /api/ai-assist and /api/slides orchestration routes
- Fixed all syntax errors and build issues
- Maintained premium blue/teal glassmorphism design

app/api/slides/route.ts

@@ -0,0 +1,37 @@
+import { NextRequest, NextResponse } from "next/server";
+import { z } from "zod";
+
+const schema = z.object({
+    topic: z.string().min(3),
+    slideCount: z.number().min(3).max(15).default(8),
+    style: z.enum(["professional", "creative", "technical", "pitch"]).default("professional"),
+});
+
+export async function POST(req: NextRequest) {
+    try {
+        const body = await req.json();
+        const { topic, slideCount, style } = schema.parse(body);
+
+        const systemPrompt = `You are an elite presentation designer. Create a visually stunning presentation with ${slideCount} slides about "${topic}".
+    
+Style: ${style}
+
+Output ONLY a sequence of slides separated by "---".
+Format each slide as:
+## [Slide Title]
+- [Bullet Point 1]
+- [Bullet Point 2]
+VISUAL: [Detailed description of image/chart/icon]
+---
+`;
+
+        // The frontend will handle the actual generation call to keep use of the ModelAdapter,
+        // this route serves as the prompt orchestrator.
+        return NextResponse.json({
+            prompt: systemPrompt,
+            success: true
+        });
+    } catch (error: any) {
+        return NextResponse.json({ success: false, error: error.message }, { status: 400 });
+    }
+}