Describe the RubyGems override and record the branch's shipping prerequisites

plans/omarchycn.md

@@ -11,6 +11,12 @@ Progress source of truth for the `omarchycn` branches of `omarchy`, `omarchy-iso
 - China to Global: switch sources and language, keep CJK fonts and the input method, remove the Claude Code third-party provider entry and the env it wrote, hide the China software entry. Dim and Kimi stay for every region.
 - Deferred provisioning and factory reset get the region's system setup but no offline input method (deferred).
 
+## Shipping prerequisites
+
+- The region screen, Rime bundling and local `rime-ice-installer` build exist only on the `omarchycn` branches: a China-ready ISO is built with `omarchy-iso/bin/omarchy-iso-make --local-source ../omarchy ../omarchy-pkgs` until they are merged and published.
+- omarchy-pkgs PR 265 (rime-ice-installer) must merge, with `omarchy-offline.patch` upstreamed to manateelazycat/rime-ice-installer, before non-local ISO builds can list it.
+- `stable-mirror.omarchy.cn`, `rc-mirror.omarchy.cn` and `mirror.omarchy.cn` must resolve for Arch packages to come from China; until then pacman falls through to `.org`.
+
 ## Tasks
 
 - [x] T0 Branches and this list