chore: use inline figures to save memory

Author: lewisjared

.binder/postBuild

@@ -13,3 +13,6 @@ bash scripts/generate_client.sh
 
 # Pre-fetch the CMIP6 sample data so notebook 04 runs without a download wait.
 python -c "from ref_tutorials import fetch_sample_data; fetch_sample_data()"
+
+# Pre-build the matplotlib font cache to save memory
+python -c "import matplotlib.pyplot as plt; plt.figure(); plt.text(0, 0, 'warm fonts'); plt.close('all')"

.binder/start

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+# Binder/repo2docker start hook. 
+# Sourced before the user's notebook server is launched, so any environment variables exported here are inherited by every kernel started in the session.
+
+# Use the non-interactive Agg backend by default to save memory
+export MPLBACKEND=Agg