feat: Implement Day 12B Great Expectations Cloud integration with comprehensive data quality validation framework

Author: raphaela-nawa

day12/README.md

@@ -6,6 +6,34 @@
 
 ---
 
+## 🎯 Two Implementations: A/B Comparison
+
+This project demonstrates **two approaches** to data quality validation, showcasing both custom framework development and enterprise tool expertise:
+
+| Aspect | **Day 12A** (Custom Framework) | **Day 12B** (GE Cloud) |
+|--------|--------------------------------|------------------------|
+| **Location** | [`day12/`](.) | [`day12b/`](../day12b) |
+| **Approach** | Custom validation framework | Great Expectations Cloud |
+| **When to Use** | Dependency issues, air-gapped environments, learning GE concepts | Production enterprise deployments, team collaboration |
+| **Dependencies** | Minimal (pandas, faker) | Full GE Cloud SDK |
+| **Data Docs** | Local HTML generation | Cloud-hosted at app.greatexpectations.io |
+| **Expectations** | Custom Python classes (10 expectations) | Native GE expectations (8 native) |
+| **Validation Results** | Local JSON files | GE Cloud storage + UI |
+| **Team Collaboration** | Single developer | Multi-user with GE Cloud |
+| **Setup Time** | <5 minutes | ~15 minutes (Cloud account required) |
+| **Portfolio Message** | "Can build validation frameworks from scratch" | "Can use enterprise data quality tools" |
+
+**💡 Why Both?**
+- **Day 12A** demonstrates problem-solving when dependencies fail (applied PIVOT RULE)
+- **Day 12B** shows proper enterprise GE Cloud integration for production use
+- Together they prove both **deep conceptual understanding** AND **practical tool expertise**
+
+**👉 Quick Start:**
+- **For Custom Framework:** Continue reading below, or jump to [Day 12A Quick Start](#how-to-use-this-project)
+- **For GE Cloud:** See [Day 12B Setup Guide](../day12b/README_12B.md)
+
+---
+
 ## Navigation
 
 ### Quick Access (By Role)

day12b/.env.example

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+# ==============================================================================
+# DAY 12B - GREAT EXPECTATIONS CLOUD CONFIGURATION
+# ==============================================================================
+# Copy this file to ../config/.env and fill in your GE Cloud credentials
+
+# Great Expectations Cloud Credentials
+# Get these from: https://app.greatexpectations.io/settings/tokens
+DAY12B_GE_CLOUD_ORG_ID=your-organization-id-here
+DAY12B_GE_CLOUD_ACCESS_TOKEN=your-access-token-here
+DAY12B_GE_CLOUD_BASE_URL=https://app.greatexpectations.io
+
+# Logging
+DAY12B_LOG_LEVEL=INFO
+
+# Notification Settings
+DAY12B_NOTIFY_ON_FAILURE=true
+DAY12B_SLACK_WEBHOOK_URL=https://hooks.slack.com/services/YOUR/WEBHOOK/URL
+
+# ==============================================================================
+# GETTING YOUR GE CLOUD CREDENTIALS
+# ==============================================================================
+# 1. Sign up at https://greatexpectations.io/cloud
+# 2. Navigate to Settings → Access Tokens
+# 3. Create a new token with "Data Context" permissions
+# 4. Copy your Organization ID from the URL or Settings page
+# 5. Paste both values above
+
+# ==============================================================================
+# USAGE
+# ==============================================================================
+# 1. Fill in your GE Cloud credentials above
+# 2. Copy to config directory: cp day12b/.env.example ../config/.env
+# 3. Run setup: python3 day12b_SETUP_cloud.py
+# 4. Create expectations: python3 day12b_CREATE_expectations.py
+# 5. Run validation: python3 day12b_RUN_validation_cloud.py
+
+# ==============================================================================
+# COMPARISON: DAY 12A vs DAY 12B
+# ==============================================================================
+# Day 12A: Custom validation framework (no GE Cloud)
+#   - Pros: Works without external dependencies, demonstrates deep understanding
+#   - Cons: Limited features, no cloud Data Docs, manual maintenance
+#
+# Day 12B: Great Expectations Cloud (this version)
+#   - Pros: Enterprise features, cloud Data Docs, team collaboration, managed infrastructure
+#   - Cons: Requires GE Cloud account, external dependency