refactor(verify): expose G36 declaration checker

[jscott3201]

Summary

• add a library target to the existing verifier package
• re-export only the fixed G36 release declaration checker
• route the existing CLI mode through that library API without changing its behavior

Boundary

This is an in-process Rust seam for the staged routine-compiler migration. It does not add a generic declaration model, PyO3, a cxf-json dependency, a Python bridge, new dependencies, schema or registry changes, generated artifacts, dependency closure, inheritance, or semantic resolution.

Validation

• scoped rustfmt check on the three changed files
• library and binary Cargo checks
• Rust tests — 20 passed
• pinned G36 declaration and source-inventory checks — 431 release and 693 development files
• routine lint suite — 189 passed
• fault replay — 137 fault directories and 1,760 scenarios passed
• dataset harness — 32 tests and the tiny FPU replay passed