[codex] extract special judge runtime

[greenthree]

What changed

• unified Schema v1 special-Judge path validation across lint, packaging, and local execution
• extracted shared Checker and Interactor execution primitives into Core
• adapted local Judge, stress, and data generation to reuse the shared runtime
• added structured responsibility, resource, cancellation, and cleanup evidence
• expanded path, fault-injection, cache, stress, data-generation, and integration tests
• preserved Windows 8.3/SUBST access spelling after canonical containment checks

Why

This is the runtime foundation for ROADMAP 2.1 Judge QA. It removes duplicated Checker/Interactor behavior before introducing judge.qa, problem-level fixtures, and evidence.

Impact

No new CLI command or Schema field is introduced in this PR. Existing standard, custom, interactive, stress, gen, and DOMjudge packaging behavior remains compatible.

Validation

• affected modules: 102 passed, 4 skipped
• path/local-Judge contract: 14 passed, 1 skipped
• npm run pack:check: 215/5 files
• git diff --check
• phtest nine-problem lint
• L02 no-cache Judge: 33 inputs, 3 solutions, 99 cases, all_expectations_met
• CI run 30970227696: all 11 Windows/Ubuntu jobs passed; all four Python 3.10/3.11 quality jobs completed the 581-test suite

A local full-suite run hit the existing 10-second detached-descendant death-confirmation timing window. The isolated test then passed in 1.5 seconds, the PID exited, temporary files were cleaned, this branch does not modify process_control.py, and both Windows CI quality jobs passed the same test.