chore: CY2026 build fails. Needs Python dependency upgrades

[mcoliver]

× Failed to build installable wheels for some pyproject.toml based projects
╰─> cryptography, pydantic-core

 error: the configured Python interpreter version (3.13) is newer than PyO3's maximum supported version (3.12)
        = help: please check if an updated version of PyO3 is available. Current version: 0.20.3
        = help: set PYO3_USE_ABI3_FORWARD_COMPATIBILITY=1 to suppress this check and build anyway using the stable ABI
      warning: build failed, waiting for other jobs to finish...
      error: `cargo rustc --lib --message-format=json-render-diagnostics --manifest-path src/rust/Cargo.toml --release -v --features pyo3/extension-module --crate-type cdylib -- -C 'link-args=-undefined dynamic_lookup -Wl,-install_name,@rpath/_rust.cpython-313-darwin.so'` failed with code 101
      [end of output]

CY2026 uses Python 3.13. Need to update our python dependencies in src/build/requirements.txt.in