phase 17: fix HTML parser NoneType attrs crash in boilerplate stripping

services/parser/html_parser.py

@@ -148,6 +148,8 @@ class ParsedDocument:
 
 def _attr_str(tag: Tag, attr: str) -> str:
     """Safely get a tag attribute as a joined string."""
+    if tag.attrs is None:
+        return ""
     val = tag.get(attr, "")
     if isinstance(val, list):
         return " ".join(val)
@@ -168,8 +170,9 @@ def _strip_boilerplate_tags(soup: BeautifulSoup) -> None:
         for tag in soup.find_all(tag_name):
             tag.decompose()
 
-    for tag in soup.find_all(True):
-        if _is_boilerplate_container(tag):
+    # Collect boilerplate tags first, then decompose to avoid iterator issues
+    to_remove = [tag for tag in soup.find_all(True) if tag.attrs is not None and _is_boilerplate_container(tag)]
+    for tag in to_remove:
         tag.decompose()