Add support for DSML wrapper aliases (<dsml|tool_calls>, <|tool_calls>,
<|tool_calls>) alongside canonical XML. Normalize mixed DSML/canonical
tags instead of rejecting them. Add tilde fence (~~~) support, fix
nested fence and unclosed fence handling, support CDATA-protected fence
content, and skip prose mentions when scanning for real tool blocks.
Mirror all changes between Go and Node.js runtimes.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>