Symbolic logic surface overview

A deterministic, code-defined capability that can be invoked from inside the orchestrator (as a stage transition, invariant, gate, or budget check), as a symbolic tool callable by the harness (policy check, scope rule, deterministic transform), or as a symbolic task callable by orchestration (validator, analyzer, scheduler, reducer, diff scanner). The symbolic-vs-agentic split is about *who is responsible for correctness* and *how results are proven*, not about where the surface lives.