json helper: migrate parsers to format.tool_call lambda pattern
- Update json_tool_call_format to use tool_call function instead of
individual tool_call_start/name_params_sep/end fields
- Migrate command-r7b, deepseek-r1, generic, lfm2, magistral,
mistral-nemo, apertus to use new pattern
- Fix quoted name handling: use + operator to avoid spaces inside quotes
- Add using Tag = common_chat_peg_tag inside lambdas
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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>