Fix Ruff FBT001 by making boolean args keyword-only and removing suppression

[Copilot]

This PR addresses FBT001 by eliminating boolean positional parameters in function signatures and removing FBT001 from the Ruff ignore list. The goal is to enforce safer, clearer call sites without changing taskflow behavior.

• Lint policy update

  • Removed FBT001 from tool.ruff.lint.ignore in pyproject.toml.

• Keyword-only boolean parameters

  • Converted boolean flags to keyword-only in targeted APIs:
    • TemplateMigrator.__init__(..., *, dry_run=False)
    • TemplateMigrator.migrate_directory(..., *, recursive=True)
    • TaskAgent.__init__(..., *, exclude_from_context=False, ...)
    • build_mcp_servers(..., *, headless=False)
    • render_model_output(..., *, log=True, async_task=False, ...)
    • _build_prompts_to_run(..., *, repeat_prompt, ...)
    • run_prompts(*, async_task=False, max_concurrent_tasks=5)
    • TaskflowSession.record_task(..., *, success, ...)
    • env_function(..., *, required=True)

• Call-site adjustments

  • Updated affected calls to pass renamed keyword-only booleans explicitly (notably in runner.py), preserving existing semantics.

Example of the pattern applied:

def build_mcp_servers(
    available_tools: AvailableTools,
    toolboxes: list[str],
    blocked_tools: list[str] | None = None,
    *,
    headless: bool = False,
) -> list[MCPServerEntry]:
    ...