docs: reorganize migration docs into dedicated subfolder

- Create docs/development/migration/ directory
- Move database-migrations.md to migration subfolder
- Move svc-006-migration-plan.md to migration subfolder
- Update all cross-references in:
  - mkdocs.yml nav configuration
  - docs/index.md
  - docs/architecture/overview.md
  - docs/backend/overview.md
  - docs/development/contributing.md
  - docs/development/troubleshooting.md
  - docs/getting-started/database-setup.md

This separates migration plans from core documentation.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

docs/architecture/overview.md

@@ -344,7 +344,7 @@ Internet ───────────│ Load Balancer│
 ### For Developers
 - [Creating a New Admin Page](../frontend/admin/page-templates.md)
 - [Backend Development Guide](../backend/overview.md)
-- [Database Migrations](../development/database-migrations.md)
+- [Database Migrations](../development/migration/database-migrations.md)
 
 ### For Operations
 - [Deployment Guide](../deployment/production.md)

docs/backend/overview.md

@@ -341,7 +341,7 @@ make migrate-create message="add_product_table"
 make migrate-up
 ```
 
-**See**: [Database Migrations](../development/database-migrations.md)
+**See**: [Database Migrations](../development/migration/database-migrations.md)
 
 ## API Documentation
 
@@ -480,5 +480,5 @@ def get_vendor_settings(vendor_id: int) -> dict:
 
 - [Middleware Reference](middleware-reference.md) - Technical API documentation
 - [Architecture Overview](../architecture/overview.md) - System architecture
-- [Database Migrations](../development/database-migrations.md) - Migration guide
+- [Database Migrations](../development/migration/database-migrations.md) - Migration guide
 - [Testing Guide](../testing/testing-guide.md) - Testing practices

docs/development/troubleshooting.md

@@ -535,4 +535,4 @@ If the issue persists:
 
 - [PyCharm Make Configuration](pycharm-configuration-make.md) - Configure Make with virtual environment
 - [Contributing Guide](contributing.md) - Development workflow
-- [Database Migrations](database-migrations.md) - Working with Alembic
+- [Database Migrations](migration/database-migrations.md) - Working with Alembic

docs/getting-started/database-setup.md

@@ -331,5 +331,5 @@ python scripts/create_landing_page.py
 
 - [Shop Setup Guide](../guides/shop-setup.md) - Configure vendor storefronts
 - [Landing Pages Guide](../features/vendor-landing-pages.md) - Customize landing pages
-- [Database Migrations Guide](../development/database-migrations.md) - Advanced migration workflows
+- [Database Migrations Guide](../development/migration/database-migrations.md) - Advanced migration workflows
 - [API Documentation](../api/index.md) - Start building features

docs/index.md

@@ -179,7 +179,7 @@ platform.com/admin                 → Admin Interface
 
     Alembic migration guide
 
-    [:octicons-arrow-right-24: Migrations](development/database-migrations.md)
+    [:octicons-arrow-right-24: Migrations](development/migration/database-migrations.md)
 
 -   :material-electron-framework:{ .lg .middle } __PyCharm Setup__
 
@@ -324,7 +324,7 @@ When running the application locally:
 
 3. **Start developing**
    - [Backend Development](backend/overview.md)
-   - [Database Migrations](development/database-migrations.md)
+   - [Database Migrations](development/migration/database-migrations.md)
    - [Testing Guide](testing/testing-guide.md)
 
 ### For Operations

mkdocs.yml

@@ -118,7 +118,7 @@ nav:
     - Customer Authentication:
       - Implementation Guide: development/customer-authentication-implementation.md
       - Quick Summary: development/customer-auth-summary.md
-    - Database Migrations: development/database-migrations.md
+    - Database Migrations: development/migration/database-migrations.md
     - Database Seeder:
       - Documentation: development/database-seeder/database-seeder-documentation.md
       - Makefile Guide: development/database-seeder/makefile-database-seeder.md