refactor(run): extract sanitizer diagnostic parsing #702

Summary

Separate sanitizer report parsing from runtime process transport and terminal
rendering.

Requirements

• Parse AddressSanitizer reports.
• Parse UndefinedBehaviorSanitizer reports.
• Parse ThreadSanitizer reports.
• Return structured diagnostics.
• Preserve original output.
• Keep terminal styling in modules/cli.

Acceptance criteria

• ASan reports produce structured diagnostics.
• UBSan reports produce structured diagnostics.
• TSan reports produce structured diagnostics.
• Runtime transport does not format diagnostics.
• Original sanitizer output remains available.
• Parser tests use stored report fixtures.