feat(codex): inject windows git bash guidance

Plan: plans/codex-windows-git-bash-profile.md

packages/omo-codex/plugin/components/rules/bundled-rules/windows-git-bash.md

@@ -0,0 +1,10 @@
+---
+description: Windows Git Bash guidance for Codex
+alwaysApply: true
+---
+
+On Windows native Codex sessions, prefer Git Bash for shell commands.
+
+Use `shell: "bash"` when `bash.exe` is on PATH. Otherwise use the absolute Git Bash path from `OMO_CODEX_GIT_BASH_PATH` or `C:\Program Files\Git\bin\bash.exe`.
+
+Use PowerShell only for Windows-native operations that need PowerShell.