fixes #4 - adds modular analyses system using plugins

app/analysis/plot_heat_user-activity-hour.py

@@ -0,0 +1,33 @@
+import pandas as pd
+import matplotlib.pyplot as plt
+import seaborn as sns
+from .basePlotAnalysis import BasePlotAnalysis
+
+import matplotlib
+matplotlib.use('Agg')
+
+class PlotActivityHeatmap(BasePlotAnalysis):
+    name = "Activity Heatmap"
+    description = "Displays user activity trends over multiple days using a heatmap. Generates a downloadable PNG image."
+    plot_filename = "activity_heatmap.png"
+    note = ""
+    
+    def transform_data(self, df: pd.DataFrame) -> pd.DataFrame:
+        """Transform data for the heatmap"""
+        active_counts = df[df['was_active']].pivot_table(
+            index='name', 
+            columns='hour', 
+            values='was_active', 
+            aggfunc='sum', 
+            fill_value=0
+        )
+        active_counts['total_active_minutes'] = active_counts.sum(axis=1)
+        return active_counts.sort_values(by='total_active_minutes', ascending=False)
+
+    def plot_data(self, df: pd.DataFrame):
+        """Generate heatmap plot"""
+        plt.figure(figsize=(12, 8))
+        sns.heatmap(df.loc[:, df.columns != 'total_active_minutes'], cmap='viridis', cbar_kws={'label': 'Count of was_active == True'})
+        plt.xlabel('Hour of Day')
+        plt.ylabel('User ID')
+        plt.title('User Activity Heatmap')