Enhance run_supy_sample with time-based data subsetting

Adds optional start and end parameters to `run_supy_sample()` function, enabling flexible temporal subsetting of sample forcing data. This improvement allows users to easily extract and simulate specific time ranges from the sample dataset without modifying the original data.

Author: sunt05

src/supy/_supy_module.py

@@ -585,6 +585,8 @@ def save_supy(
 
 
 def run_supy_sample(
+    start=None,
+    end=None,
     save_state=False,
     chunk_day=3660,
     logging_level=logging.INFO,
@@ -631,6 +633,14 @@ def run_supy_sample(
     # Load sample data
     df_state_init, df_forcing = load_sample_data()
 
+    # subset forcing data
+    if start is not None:
+        df_forcing = df_forcing[start:]
+    if end is not None:
+        df_forcing = df_forcing[:end]
+    if start is not None and end is not None:
+        df_forcing = df_forcing[start:end]
+
     # Run SuPy with the sample data
     df_output, df_state_final = run_supy(
         df_forcing=df_forcing,