feat: port contexts layer and MCP parity

app/api/contexts/[id]/nodes/route.ts

@@ -0,0 +1,22 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { contextService } from '@/services/database';
+
+export const runtime = 'nodejs';
+
+export async function GET(
+  request: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  try {
+    const { id } = await params;
+    const contextId = parseInt(id, 10);
+    if (Number.isNaN(contextId)) {
+      return NextResponse.json({ success: false, error: 'Invalid context ID' }, { status: 400 });
+    }
+
+    const nodes = await contextService.getNodesForContext(contextId);
+    return NextResponse.json({ success: true, data: nodes, count: nodes.length });
+  } catch (error) {
+    return NextResponse.json({ success: false, error: error instanceof Error ? error.message : 'Failed to fetch context nodes' }, { status: 500 });
+  }
+}