chore(security): enhance environment configuration, CI workflows, and wallet daemon with security improvements

- Restructure .env.example with security-focused documentation, service-specific environment file references, and AWS Secrets Manager integration
- Update CLI tests workflow to single Python 3.13 version, add pytest-mock dependency, and consolidate test execution with coverage
- Add comprehensive security validation to package publishing workflow with manual approval gates, secret scanning, and release

docs/19_marketplace/gpu_monetization_guide.md

@@ -0,0 +1,68 @@
+---
+title: GPU Monetization Guide
+summary: How to register GPUs, set pricing, and receive payouts on AITBC.
+---
+
+# GPU Monetization Guide
+
+## Overview
+This guide walks providers through registering GPUs, choosing pricing strategies, and understanding the payout flow for AITBC marketplace earnings.
+
+## Prerequisites
+- AITBC CLI installed locally: `pip install -e ./cli`
+- Account initialized: `aitbc init`
+- Network connectivity to the coordinator API
+- GPU details ready (model, memory, CUDA version, base price)
+
+## Step 1: Register Your GPU
+```bash
+aitbc marketplace gpu register \
+  --name "My-GPU" \
+  --memory 24 \
+  --cuda-version 12.1 \
+  --base-price 0.05
+```
+- Use `--region` to target a specific market (e.g., `--region us-west`).
+- Verify registration: `aitbc marketplace gpu list --region us-west`.
+
+## Step 2: Choose Pricing Strategy
+- **Market Balance (default):** Stable earnings with demand-based adjustments.
+- **Peak Maximizer:** Higher rates during peak hours/regions.
+- **Utilization Guard:** Keeps GPU booked; lowers price when idle.
+- Update pricing strategy: `aitbc marketplace gpu update --gpu-id <id> --strategy <name>`.
+
+## Step 3: Monitor & Optimize
+```bash
+aitbc marketplace earnings --gpu-id <id>
+aitbc marketplace status --gpu-id <id>
+```
+- Track utilization, bookings, and realized rates.
+- Adjust `--base-price` or strategy based on demand.
+
+## Payout Flow (Mermaid)
+```mermaid
+sequenceDiagram
+  participant Provider
+  participant CLI
+  participant Coordinator
+  participant Escrow
+  participant Wallet
+
+  Provider->>CLI: Register GPU + pricing
+  CLI->>Coordinator: Submit registration & terms
+  Coordinator->>Escrow: Hold booking funds
+  Provider->>Coordinator: Deliver compute
+  Coordinator->>Escrow: Confirm completion
+  Escrow->>Wallet: Release payout to provider
+```
+
+## Best Practices
+- Start with **Market Balance**; adjust after 48h of data.
+- Set `--region` to match your lowest-latency buyers.
+- Update CLI regularly for the latest pricing features.
+- Keep GPUs online during peak windows (local 9 AM – 9 PM) for higher fill rates.
+
+## Troubleshooting
+- No bookings? Lower `--base-price` or switch to **Utilization Guard**.
+- Low earnings? Check latency/region alignment and ensure GPU is online.
+- Command help: `aitbc marketplace gpu --help`.