docs(rock3/rock3b): widen Maskrom erase pin images from 500 to 1200

[tangzz-radxa]

Summary

• Bump the rendered display width of the ROCK 3B / 3B+ Maskrom pin reference images from 500 to 1200 in docs/rock3/rock3b/low-level-dev/maskrom/erase.md, so the pin labels and silkscreen markings stay legible at typical docs viewport sizes.
• Mirror the same change in the English translation at i18n/en/docusaurus-plugin-content-docs/current/rock3/rock3b/low-level-dev/maskrom/erase.md so the two languages stay in sync.

Scope

• 2 files, 4 lines changed
• Pure docs / docs-i18n touch, no code, no script, no asset
• Affects only the ROCK 3B / ROCK 3B+ tab in the Maskrom erase tutorial

Why

The original width="500" makes the pinout reference images render quite small in the side-by-side Maskrom tab view, and several readers (including on mobile widths) reported having to open the image in a new tab to read the silkscreen. 1200 matches the wider render convention used in other recent ROCK 3B tutorials and keeps the image inside the normal docs column at common viewport sizes.

Files

• docs/rock3/rock3b/low-level-dev/maskrom/erase.md — ROCK 3B and ROCK 3B+ <img ... width="500" /> -> width="1200"
• i18n/en/docusaurus-plugin-content-docs/current/rock3/rock3b/low-level-dev/maskrom/erase.md — same change in the English version

Checklist

• Both Chinese (docs/) and English (i18n/en/) updated together
• Only the targeted image width attribute changed; no other lines touched
• Branched from upstream-docs/main and github_pr_guard passes (ok: true, bilingual clean)