Feature request: add write protection support

[dariocorse]

I’ve implemented raw config write support for wchisp in my fork and tested it on CH32V203C8T6 and would like to propose it for inclusion.

It adds wchisp config set , which accepts either:

• the 12 writable config bytes, or
• the full 24-byte config info dump, in which case only the first 12 writable bytes are written back.

The implementation performs a readback check after writing.

Because protection-related config changes can be risky on some chips, I wanted to check whether you’d accept a PR before I open one.

Tested on:

• chip: CH32V203C8T6
• bootloader version: 02.70
• transport: USB ISP

Safety notes:

• On this chip, the feature is reversible: I was able to restore the previous state by writing back the corresponding config bytes, and config unprotect also restores the unprotected state.
• On my device, RDPR affects readout, but WRP does not appear to block USB ISP flashing via wchisp. In addition, WCH-Link / wlink flash appears to implicitly clear both read and write protection before
  flashing.
• I have only tested this on CH32V203C8T6. I have not validated the behavior on other families yet, especially chips with known config-read/write quirks.

I can also add docs/help text and warnings if that would make the PR more useful.