Add database auto-creation and fix IFC parser flush logic

- Create tables on application startup via lifespan event
- Flush project before creating elements (generate project_id)
- Flush each element before creating properties (generate element_id)
- Add IfcWallStandardCase to parsed element types
- Include FZK-Haus sample IFC file for testing
- Tested: 58 elements, 3601 properties parsed successfully

backend/app/services/ifc_parser.py

@@ -38,10 +38,11 @@ async def parse_ifc_file(
         ifc_schema=ifc.schema,
     )
     db.add(project)
+    await db.flush()
 
     # Extract elements
     element_types = [
-        "IfcWall", "IfcDoor", "IfcWindow", "IfcSlab",
+        "IfcWall", "IfcWallStandardCase", "IfcDoor", "IfcWindow", "IfcSlab",
         "IfcColumn", "IfcBeam", "IfcStair", "IfcRoof",
         "IfcSpace", "IfcFurnishingElement", "IfcBuildingElementProxy",
     ]
@@ -59,6 +60,7 @@ async def parse_ifc_file(
                 storey=storey,
             )
             db.add(element)
+            await db.flush()
 
             # Extract property sets
             for pset_name, props in _get_properties(ifc_element).items():
@@ -75,7 +77,6 @@ async def parse_ifc_file(
     await db.refresh(project)
     return project
 
-
 def _extract_project_name(ifc, fallback_filename: str) -> str:
     """Try to get the project name from the IFC file."""
     try: