fix(chart): correct quarterly label format from QQ1 to Q1

src/charts/spending_debt.py

@@ -30,7 +30,7 @@ def plot_hyperscaler_capex() -> str:
     ]
 
     x_labels = [str(y) for y in annual_years] + [
-        f"{y}-Q{q}" for y, q in quarterly_periods
+        f"{y}-{q}" for y, q in quarterly_periods
     ]
     n_periods = len(x_labels)
     x_positions = list(range(n_periods))