Fix Python namespace package imports

[hardbyte]

Summary

• import and bind parent Python packages whenever generated child modules reference parent-qualified types
• add deferred same-root sibling placeholders plus intermediate package binding for deep namespace imports
• sanitize generated Python class names for invalid namespace characters and avoid stdlib sys shadowing
• clean stale generated files from CLI directory outputs via a generated-file manifest

Validation

• cargo test -p reflectapi-cli --test output_paths -- --nocapture
• cargo test -p reflectapi-demo test_python_split_modules -- --nocapture
• cargo test -p reflectapi-demo tests::write_python_client -- --nocapture
• issue Python codegen: missing from ... import <parent> when a submodule references only top-level parent types #158 generated repro: ruff --select F821 + import/rebuild
• adversarial generated probe: ruff --select F821 + compileall + import/rebuild
• checked-in demo Python client: ruff --select F821 + import

[github-actions]

📖 Documentation Preview: https://reflectapi-docs-preview-pr-159.partly.workers.dev

Updated automatically from commit 1cbc381

[chatgpt-codex-connector]

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