docs: add max_old_tool_call_tokens and max_consecutive_tool_calls to agent config reference

[dgageot]

Fixes #2228

Adds documentation for max_old_tool_call_tokens and max_consecutive_tool_calls to the agent configuration reference page:

• Added both properties to the YAML schema block
• Added both properties to the properties reference table with descriptions and defaults
  • max_old_tool_call_tokens: default 40000, set to -1 to disable truncation
  • max_consecutive_tool_calls: default 5

[docker-agent]

Assessment: 🟢 APPROVE

This documentation change adds two new agent configuration parameters to the reference documentation:

• max_consecutive_tool_calls: Maximum consecutive identical tool calls (default: 5)
• max_old_tool_call_tokens: Token budget for old tool call content (default: 40000, -1 to disable)

The additions are consistent with the schema and implementation. No issues found in the changed code.