Use urlencode for building Discourse redirect URL

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -1 +1,2 @@
 config.yaml
+/venv/

app.py

@@ -2,6 +2,7 @@ import argparse
 import base64
 import json
 import secrets
+from urllib.parse import urlencode
 
 import yaml
 from cryptography.hazmat.primitives import serialization
@@ -46,8 +47,7 @@ def authorize():
         "nonce": nonce,
         "public_key": public_key,
     }
-    query = "&".join(f"{k}={v}" for k, v in params.items())
-    return redirect(f"{config['forum_url']}/user-api-key/new?{query}")
+    return redirect(f"{config['forum_url']}/user-api-key/new?{urlencode(params)}")
 
 
 @app.route("/callback")