Align TypeAliasType constructor binding and validation - #9687

Summary

• Replace manual TypeAliasType argument parsing with shared raw FromArgs/bind_for handling.
• Require native type parameters before evaluating defaults, propagate lazy-default and repr exceptions, and preserve surrogate code points in diagnostics.
• Normalize empty parameter tuples while retaining original inputs through metadata capture and allocation.
• Read the caller function's module metadata through existing frame APIs.

Reference: CPython 3.15.0 TypeAliasType construction and type-parameter validation and generated Clinic wrappers.

Validation

• Independent source review and bounded CPython 3.15 reference probes cover exact parameter types, lazy-default/invalid-repr exceptions, tuple subclasses and lifetimes, None versus omitted arguments, caller metadata, and surrogate diagnostics.
• Formatting and whitespace checks passed.
• Normal commit hooks passed.
• Focused cargo check --locked --offline -j1 -p rustpython-host_env -p rustpython-vm -p rustpython-stdlib --features rustpython-stdlib/threading passed.
• Strict Clippy with the same packages/features and -- -D warnings passed. This is a focused threading-enabled subset of CI, not the full workspace/all-targets suite.
• RustPython runtime, full workspace/C-API suites and cross-platform execution were not run. No test, Lib, workflow or marker edits.

Shared-binder mixed-invalid error precedence and wording remain different from Clinic in some combinations. This change adds no bespoke parser or VM frame architecture changes, and is independent of the TypeVar constructor group.

AI assistance: OpenAI Codex performed source comparison, implementation, reference probes and independent source review; model version was not exposed.