Add streamlit endpoint and fix deployment

Author: bprobert97

README.md

@@ -2,6 +2,8 @@
 
 Scripts in this repository generate images of the night sky as seen in Glasgow, UK using the [Starplot](https://starplot.dev/) library.
 
+If you just want to generate plots, rather than contribute to the code, you can do so for free at: https://glasgow-starplot.streamlit.app/
+
 # Examples
 
 ![A Zenith Star Plot from Glasgow](images/glasgow_zenith.png "A Zenith Star Plot from Glasgow")

app.py

@@ -20,12 +20,18 @@
 
 """
 
+import os
 import streamlit as st
 from datetime import datetime, date
 from zoneinfo import ZoneInfo
 from scripts.glasgow_horizon import make_horizon_plot
 from scripts.glasgow_zenith import make_zenith_plot
 
+# Fix DuckDB/Starplot permissions
+os.makedirs("duckdb_extensions", exist_ok=True)
+os.environ["IBIS_DUCKDB_LIBDIR"] = os.path.abspath("duckdb_extensions")
+
+
 st.title("🌌 Glasgow Starplot Viewer")
 
 # Sidebar: Plot type