Clarify non-reset behavior of Gray counter in `cdc_strobe` for ASIC compatibility

[JacyCui]

Hi, thanks for providing such a clean CDC module!

I noticed that the Gray code counter gc_FP_ATTR is intentionally not reset:

// 2 bit gray counter, it must NEVER be reset
logic [1:0] gc_FP_ATTR = '0;

This makes sense in the context of CDC synchronization — resetting the counter could cause a spurious strobe in the clk2 domain due to mismatch or metastability.
That said, some users (especially targeting ASICs or formal tools) might be surprised by the absence of a reset or the reliance on simulation-only initial values (gc_FP_ATTR = '0).

Would it make sense to:

• Add a comment clarifying that the counter should not be reset to prevent CDC issues?
• Note that this design may not be portable to ASIC synthesis without further careful handling of initial values?

Thanks again for the great work — and for the detailed comments throughout the code!