Add professional documentation for multi-engine database architecture in README

README.md

@@ -73,6 +73,14 @@ The CMS reads emulator-owned tables (`users`, `items`, `rooms`, `bans`, etc.) di
 
 > **Note:** The CMS does **not** own the emulator schema — it maps to those tables via Drizzle. Never run `drizzle-kit push` / `migrate` against the shared DB. CMS-owned tables (`website_*`, `radio_*`, etc.) are created via idempotent SQL in `drizzle/migrations/`.
 
+#### Multi-Engine Architecture & Dialect Routing
+
+EpicNext-CMS features a robust, multi-dialect database abstraction layer powered by **Drizzle ORM**. Depending on the connection string protocol supplied in `DATABASE_URL`:
+- **MySQL / MariaDB (`mysql://`)**: Utilizes `mysql2/promise` connection pooling with optimized keep-alive, named placeholders, and strict statement hardening.
+- **PostgreSQL (`postgres://` / `postgresql://`)**: Utilizes `node-postgres` (`pg.Pool`) with high-performance async client handling.
+
+The query builder and helper functions (`queryRows`, `execResult`, `affectedRows`) automatically normalize driver-specific responses (`ResultSetHeader` vs PostgreSQL result objects), ensuring seamless compatibility across database engines without application-layer changes.
+
 ### 3. Configure Environment
 
 ```bash