fix(python-sdk): preserve boolean defaults in agent CLI calls - #1151

Summary

When python main.py call omits a boolean option, it passes False to the skill or reasoner even if the function declares a default of True. Use the function's declared default when the option is omitted. A supplied flag still enables the option, and a boolean parameter without a declared default still falls back to False.

Type of change

• Bug fix

Test plan

• Run the CLI tests. Both new cases reproduced the bug on the base commit. After the fix, 19 passed and 1 existing test was skipped.
• Run ./scripts/test-all.sh. The Go control plane and Go SDK passed. Python SDK reported 2,950 passed, TypeScript SDK core reported 1,383 passed, and Web UI reported 837 passed.
• Run make fmt tidy, Python SDK Ruff and mypy, memory-event tests with websockets 12.0 and 15.0.1 (28 passed each), and the Python performance benchmark.

Test coverage

• I ran tests for the surface I changed locally.
• The CLI regression covers an omitted default-on option, an omitted default-off option, and an explicitly supplied flag.
• The coverage gate check is green in CI before requesting review. Pending CI.

Checklist

• I read docs/CONTRIBUTING.md and docs/DEVELOPMENT.md.
• Commits are signed and follow Conventional Commits. The commit follows Conventional Commits and is unsigned.