Respect TypedDict required fields

[alexdrydew]

Summary

• preserve TypedDict required/optional key metadata through normalization and Rust type models
• avoid using non-required TypedDict keys as attribute-source candidates
• allow TypedDict synthesis to omit unresolved non-required fields
• add regressions for total=False, NotRequired, Required overrides, and optional synthesis

Checks

• make fmt-rust-check
• make ruff
• make basedpyright
• make test