add uv tree solution

Author: SkafteNicki

s1_development_environment/package_manager.md

@@ -256,6 +256,8 @@ to make it work.
 
             ```bash
             uv pip list
+            # or
+            uv tree
             ```
 
 4. The above is the very basic of `uv` and is actually not the recommended way of using `uv`. Instead, `uv` works best

tools/course_stats/viz.py

@@ -24,8 +24,8 @@
 @app.command()
 def plot_students():
     """Plot the number of students over the years."""
-    year = [2021, 2022, 2023, 2024, 2025]
-    students = [60, 102, 196, 275, 374]
+    year = [2021, 2022, 2023, 2024, 2025, 2026]
+    students = [60, 102, 196, 275, 374, 450]
 
     # Calculate year-over-year percentage increase
     percentage_increase = [0]  # No increase for the first year