feat(domains): ✨ add domain support for DrawDB integration

- Introduce Domain and DomainTable models for logical grouping of tables.
- Implement export and import functionality for domains in DrawDB format.
- Update template execution modes to include domain processing.
- Enhance documentation for domain features and usage.

docs/TEMPLATE_MODE.md

@@ -44,12 +44,13 @@ The `--mode` flag controls how the template is executed:
 |------|-------------|--------|-------------|
 | `database` | Execute once for entire database | Single file | Documentation, reports, overview files |
 | `schema` | Execute once per schema | One file per schema | Schema-specific documentation |
+| `domain` | Execute once per domain | One file per domain | Domain-based documentation, domain exports |
 | `script` | Execute once per script | One file per script | Script processing |
 | `table` | Execute once per table | One file per table | Model generation, table docs |
 
 ### Filename Patterns
 
-For multi-file modes (`schema`, `script`, `table`), use `--filename-pattern` to control output filenames:
+For multi-file modes (`schema`, `domain`, `script`, `table`), use `--filename-pattern` to control output filenames:
 
 ```bash
 # Default pattern
@@ -296,6 +297,13 @@ The data available in templates depends on the execution mode:
 .Metadata          // map[string]interface{} - User metadata
 ```
 
+### Domain Mode
+```go
+.Domain            // *models.Domain - Current domain
+.ParentDatabase    // *models.Database - Parent database context
+.Metadata          // map[string]interface{} - User metadata
+```
+
 ### Table Mode
 ```go
 .Table             // *models.Table - Current table
@@ -317,6 +325,7 @@ The data available in templates depends on the execution mode:
 **Database:**
 - `.Name` - Database name
 - `.Schemas` - List of schemas
+- `.Domains` - List of domains (business domain groupings)
 - `.Description`, `.Comment` - Documentation
 
 **Schema:**
@@ -325,6 +334,17 @@ The data available in templates depends on the execution mode:
 - `.Views`, `.Sequences`, `.Scripts` - Other objects
 - `.Enums` - Enum types
 
+**Domain:**
+- `.Name` - Domain name
+- `.Tables` - List of DomainTable references
+- `.Description`, `.Comment` - Documentation
+- `.Metadata` - Custom metadata map
+
+**DomainTable:**
+- `.TableName` - Name of the table
+- `.SchemaName` - Schema containing the table
+- `.RefTable` - Pointer to actual Table object (if loaded)
+
 **Table:**
 - `.Name` - Table name
 - `.Schema` - Schema name