docs: reconstruct READMEs

datahub/README.md

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+# DataHub
+
+Modern data catalog and metadata management platform:
+
+- Centralized data discovery and documentation
+- Data lineage tracking and impact analysis
+- Schema evolution monitoring
+- OIDC integration with Keycloak for secure access
+- Elasticsearch-powered search and indexing
+- Kafka-based real-time metadata streaming
+- PostgreSQL backend for metadata storage
+
+## Installation
+
+```bash
+just datahub::install
+```
+
+## Resource Requirements
+
+> **⚠️ Resource Requirements:** DataHub is resource-intensive, requiring approximately **4-5GB of RAM** and 1+ CPU cores across multiple components (Elasticsearch, Kafka, Zookeeper, and DataHub services). Deployment typically takes 15-20 minutes to complete. Ensure your cluster has sufficient resources before installation.
+
+## Access
+
+Access DataHub at `https://datahub.yourdomain.com` and use "Sign in with SSO" to authenticate via Keycloak.