Refactor URL creation to use reusable join_url utility

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

app/utils/network.py

@@ -32,3 +32,16 @@ def is_private_ip(hostname: str) -> bool:
             # Log this for debugging
             logger.warning(f"Could not resolve hostname: {hostname}")
             return False  # Changed from True to False to allow external domains in tests
+
+
+def join_url(base: str, *parts: str) -> str:
+    """
+    Safely join a base URL and multiple path parts.
+    Handles double slashes while preserving the protocol '://'.
+    """
+    url = "/".join([base, *parts])
+    url = url.replace("://", "$PLACEHOLDER$")
+    while "//" in url:
+        url = url.replace("//", "/")
+    url = url.replace("$PLACEHOLDER$", "://")
+    return url