feat(05-01): create image serving API endpoint

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/app/api/images/[id]/route.ts

@@ -0,0 +1,41 @@
+/**
+ * Image Serving API Endpoint
+ *
+ * Serves temporarily stored images via URL for external providers.
+ * Images are stored in memory and should be cleaned up by callers after use.
+ *
+ * GET /api/images/[id] - Retrieve stored image by ID
+ */
+
+import { NextRequest, NextResponse } from "next/server";
+import { getImage } from "@/lib/images/store";
+
+/**
+ * GET handler - serve stored image
+ */
+export async function GET(
+  request: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+): Promise<NextResponse> {
+  const { id } = await params;
+
+  const image = getImage(id);
+
+  if (!image) {
+    return NextResponse.json(
+      { error: "Image not found" },
+      { status: 404 }
+    );
+  }
+
+  // Convert Buffer to Uint8Array for NextResponse compatibility
+  const uint8Array = new Uint8Array(image.data);
+
+  return new NextResponse(uint8Array, {
+    status: 200,
+    headers: {
+      "Content-Type": image.mimeType,
+      "Cache-Control": "no-store",
+    },
+  });
+}