fix streaming diff bugs for Command R7B and Mistral Nemo
- Make native mapper create tool calls lazily on TOOL_NAME, not TOOL_OPEN
- Buffer pending TOOL_ID when it comes before TOOL_NAME (Command R7B format)
- Add is_partial check for TOOL_ID to skip incomplete IDs
- Fix test_parser_with_streaming to distinguish new vs updated tool calls
- Integrate test_parser_with_streaming into needle test suite
- Improve parse error messages with context
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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
