Function strip_backlog_patch_attr 

pub fn strip_backlog_patch_attr(doc: &str) -> String

Strip deprecated patch=... (and legacy mode=...) attributes from backlog/pending component opening tags. The backlog component’s patch mode is always replace by built-in default; the inline attribute is redundant since the binary owns all backlog mutations via --pending-* flags.

Emits a deprecation warning to stderr for each stripped attribute.