DEN-3828: publish reusable TJSV admission workflow for Zed repositories #67

Create one canonical reusable workflow/action for Zed repositories that consume independently authored TypeSpec + JSON Schema contracts through ORESoftware/typespec-json-schema-validator.

Acceptance:

• immutable TJSV revision and exact reviewed-head assertion;
• dense expected-declaration inventory;
• current-input consumer verification / verify-ir receipt;
• generated JSON Schema remains comparison evidence only;
• positive admission plus canonical refusal probes;
• clean producer/validator checkout checks before and after;
• report / Contract IR / verification artifacts retained;
• no second CLI parser; TJSV/flags-2-env remains the option authority;
• migrate at least 3 existing Zed consumers without weakening native/runtime gates.

Linear parent: DEN-3828. Related: DEN-3959, DEN-3982.