debug: comprehensive error handling and logging for list_goals

- try-catch around entire endpoint
- try-catch for each goal progress update
- Detailed error logging with traceback
- Continue processing other goals if one fails
- Clear error message to frontend

This will show exact error location in logs.

backend/routers/goals.py

@@ -161,6 +161,7 @@ def list_goals(session: dict = Depends(require_auth)):
     """List all goals for current user"""
     pid = session['profile_id']
 
+    try:
         with get_db() as conn:
             cur = get_cursor(conn)
             cur.execute("""
@@ -176,13 +177,27 @@ def list_goals(session: dict = Depends(require_auth)):
             """, (pid,))
 
             goals = [r2d(row) for row in cur.fetchall()]
+            print(f"[DEBUG] Loaded {len(goals)} goals for profile {pid}")
 
             # Update current values for each goal
             for goal in goals:
+                try:
                     _update_goal_progress(conn, pid, goal)
+                except Exception as e:
+                    print(f"[ERROR] Failed to update progress for goal {goal.get('id')}: {e}")
+                    # Continue with other goals even if one fails
 
             return goals
 
+    except Exception as e:
+        print(f"[ERROR] list_goals failed: {e}")
+        import traceback
+        traceback.print_exc()
+        raise HTTPException(
+            status_code=500,
+            detail=f"Fehler beim Laden der Ziele: {str(e)}"
+        )
+
 @router.post("/create")
 def create_goal(data: GoalCreate, session: dict = Depends(require_auth)):
     """Create new goal"""