feat: add project base path and template path handling in report generation

- Introduced PROJECT_BASE_PATH constant for consistent project directory reference.
- Updated Reports class to require template_path for loading HTML templates.
- Modified DataManagerRepository to pass the new template_path when generating reports.

model_manager/sientia/reports.py

@@ -68,7 +68,7 @@ class Reports:
     """
 
     def __init__(
-        self, reference_data: Any, current_data: Any, target_name: str, base_path: str | None = None
+        self, reference_data: Any, current_data: Any, target_name: str, base_path: str | None = None, template_path: str | None = None
     ) -> None:
         """
         Initializes an instance of the AigReport class.
@@ -87,6 +87,7 @@ class Reports:
         self.target_name = target_name
         self.set_color_options(primary_color='#0F4C81', secondary_color='#001E60')
         self.base_path = base_path
+        self.template_path = template_path
 
     def add_data_quality_section(self, columns: list[str] | None = None, run: bool = True) -> None:
         """
@@ -238,6 +239,9 @@ class Reports:
         if not self.base_path:
             raise ValueError('base_path is required to save all sections HTML')
 
+        if not self.template_path:
+            raise ValueError('template_path is required to save all sections HTML')
+
         # Ensure output directory exists
         output_dir = os.path.dirname(report_path)
         if output_dir and not os.path.exists(output_dir):
@@ -248,7 +252,7 @@ class Reports:
         print(f"Base path: {self.base_path}")
 
         # Load main HTML template
-        main_html_path = os.path.join(self.base_path, 'header.html')
+        main_html_path = os.path.join(self.template_path, 'header.html')
         main_html = load_html_from_file(main_html_path)
 
         # Load content from data_drift.html, data_quality.html, and regression.html