- introduce removeChatToolbarCustomShortcutFn in toolbar_remove_custom.go
as a package-level injection seam; default impl routes through
callMCPToolOnServer against the im server so production behavior is
unchanged
- update RunE to dispatch via the seam instead of calling
callMCPToolOnServer inline
- add two TestCrossPlatformCoverage* tests that swap the seam via
testseam.Swap and verify: (1) without --yes the seam is never called
and a typed confirmation_required error is returned, (2) with --yes
the seam is called exactly once with openCid and shortcutId. The
stub forwards to deps.Caller.CallTool so the user_required contract
gate (leaf.go) still sees the CallTool channel.
xlb1130