entropy_ring_nand2_wrapper

Wrap ring-oscillator stage primitives with simulation-only propagation delay.

entropy_ring_oscillator is a free-running combinational loop; without delay, RTL simulation never advances time because every stage settles in the same delta cycle.

Real delay comes from whichever prim_clock_nand2 / prim_buf / prim_stdmux2 flavor synthesis binds each stage to. The generic and technology-specific flavors are swapped in as a group per build target, so every flavor keeps the same port list and none carries a delay parameter. Each wrapper instances one unmodified prim and adds a #1 delay only when neither SYNTHESIS nor EMULATION is defined, so synthesis, emulation and every other consumer of those prims see the ordinary zero-delay cell. In the emulation view the ring is a zero-delay combinational loop that the emulator compile must break or model.