fix(renderer): remove ambiguous \s* from _parse_if regex to prevent ReDoS

The pattern \s*(.+?)\s* in _parse_if allowed polynomial backtracking
when no closing }} was found — confirmed to hang at n=5000 whitespace
chars. The \s* wrappers were redundant since group(1) is already
stripped at the call site.

Reported and patched with @pa1va. Closes #2326

Scripts/python/src/theming/lib/renderer.py

@@ -359,7 +359,7 @@ class TemplateRenderer:
             condition_part = condition_part[4:].strip()
 
         # Extract expression from {{ ... }} if present
-        expr_match = re.match(r'\{\{\s*(.+?)\s*\}\}', condition_part)
+        expr_match = re.match(r'\{\{(.+?)\}\}', condition_part)
         if expr_match:
             condition_expr = expr_match.group(1).strip()
         else: