Use VM callbacks with AI recovery and full test coverage

[sunmodza]

Changes

• Route simple annotated module assignments through patched CPython VM store callbacks by default. The same route adds statement checkpoints when AI recovery is configured.
• Keep callback registrations tied to code object identity and their owning runtime, retain module type scopes for recovery, and avoid sharing registered VM code across runtimes.
• Validate variadic parameter rebinding through native callbacks and keep callback shutdown safe.
• Add regression tests for VM routing, recovery, typed yields, CLI state restoration, and version-specific type behavior.

Verification

• Stock CPython 3.11.16, 3.12.14, 3.13.15, and 3.14.4: 584 tests pass on each version; line and branch coverage are both 100.00% on each version under scripts/coverage_summary.py.
• Patched CPython 3.11.16–3.14.4: 584 tests pass on each version; native bridge and VM hook smoke tests pass.
• Source distribution and wheel build successfully.

Scope

The native VM route covers simple annotated module assignments, including configured AI recovery. Typed yields and other typed source continue through the boundary compiler. Full behavioral equivalence with CPython remains outside this PR's claim; Aiython's annotation checks and AI recovery intentionally add behavior.