feat(src/djinit/templates/project): update env template placeholder and add optional database URL dependency

New Features
- Add optional `dj-database-url` dependency for database URL support.

Enhancements
- Replace `{{ project_name }}` with `[[ project_name ]]` in the env template for clearer interpolation.

Bug Fixes
- None

src/djinit/templates/project/env_sample-tpl

@@ -1,5 +1,5 @@
 # Django settings
-DJANGO_SETTINGS_MODULE={{ project_name }}.settings.development
+DJANGO_SETTINGS_MODULE=[[ project_name ]].settings.development
 SECRET_KEY=your-secret-key
 ALLOWED_HOSTS=api.your-domain.com,www.your-domain.com
 

src/djinit/templates/project/pyproject.toml-tpl

@@ -19,6 +19,9 @@ dependencies = [
 # @ENDIF
 # @IF database_type == 'postgresql'
     "psycopg2-binary",
+# @ENDIF
+# @IF use_database_url
+    "dj-database-url",
 # @ENDIF
     "gunicorn",
 ]