Add comprehensive documentation for employee learning platform

- Created handover document outlining design decisions and application functionality.
- Developed implementation plan detailing phased approach for service development.
- Specified ingestion service responsibilities, API surface, and processing pipeline.

app/services/ingestion/src/index.ts

@@ -0,0 +1,18 @@
+import 'dotenv/config';
+import Fastify from 'fastify';
+import documentRoutes from './routes/documents.js';
+
+const PORT = parseInt(process.env['INGESTION_PORT'] ?? '3001', 10);
+
+async function start(): Promise<void> {
+  const app = Fastify({ logger: true });
+
+  await app.register(documentRoutes);
+
+  await app.listen({ port: PORT, host: '0.0.0.0' });
+}
+
+start().catch((err: unknown) => {
+  console.error('Failed to start ingestion service:', err);
+  process.exit(1);
+});