feat: add marketplace metrics, privacy features, and service registry endpoints

- Add Prometheus metrics for marketplace API throughput and error rates with new dashboard panels
- Implement confidential transaction models with encryption support and access control
- Add key management system with registration, rotation, and audit logging
- Create services and registry routers for service discovery and management
- Integrate ZK proof generation for privacy-preserving receipts
- Add metrics instru

docs/user-guide/overview.md

@@ -0,0 +1,27 @@
+---
+title: User Guide Overview
+description: Learn how to use AITBC as a user
+---
+
+# User Guide Overview
+
+Welcome to the AITBC user guide! This section will help you understand how to interact with the AITBC platform.
+
+## What You'll Learn
+
+- Creating and submitting AI jobs
+- Using the marketplace
+- Managing your wallet
+- Monitoring your jobs
+- Understanding receipts and proofs
+
+## Getting Started
+
+If you're new to AITBC, start with the [Quickstart Guide](../getting-started/quickstart.md).
+
+## Navigation
+
+- [Creating Jobs](creating-jobs.md) - Learn to submit AI workloads
+- [Marketplace](marketplace.md) - Buy and sell AI services
+- [Explorer](explorer.md) - Browse the blockchain
+- [Wallet Management](wallet-management.md) - Manage your funds