fix: repair clone-repos.sh URL filter that skipped every repo [#632]

The old condition only accepted lines that contained whitespace, so
every plain URL was skipped and the script was a silent no-op (0/0
clones). Strip each line and process all non-empty URLs.

Detail: https://projects.knownelement.com/issues/632#note-1

💘 Generated with Crush

Assisted-by: Crush:glm-5.2

clone-repos.sh

@@ -108,7 +108,8 @@ successful_clones=0
 failed_clones=0
 
 while IFS= read -r url; do
-    if [ -n "$url" ] && [ "$url" != "$(echo "$url" | tr -d '[:space:]')" ]; then
+    url=$(printf '%s' "$url" | tr -d '[:space:]')
+    if [ -n "$url" ]; then
         total_repos=$((total_repos + 1))
         
         # Extract repository name from URL