fix(load): strip the deferred atinit marker on both branches

[ss-o]

Fixes the reported defect and a second one of the same kind, found next to it.

Two branches, two defects

atinit'!...' defers the hook, and the ! has to be stripped before the body is evaluated. Two branches strip it, and each was wrong in a different way.

The nocd branch of the source path, reported in #445, stripped 1 instead of !:

eval "${ICE[atinit]#1}"

The body then ran as a command named !typeset.

The command branch put the strip inside the subscript:

eval "${ICE[atinit#!]}"

That looks up an ICE key named atinit#!, finds nothing, and evaluates the empty string:

zsh -fc 'typeset -A ICE=( atinit "!print ran" )
         print "[${ICE[atinit#!]}]"   # []
         print "[${ICE[atinit]#!}]"'  # [print ran]

This one is silent: no error, no hook, and the load reports success. It was not in the report, and it affects as"command" plug-ins without nocd, which is the ordinary case for that branch.

Reproduced

CASE as-command atinit-bang:   MARK_CMD=unset     (no diagnostic at all)
CASE normal+nocd atinit-bang:  MARK_NORM=unset    ((eval):1: command not found: !typeset)

Both sites now read ${ICE[atinit]#!}, matching the two other strips in the file.

Test

tests/atinit-deferred-marker.zsh loads an as"command" plug-in without nocd and a normal plug-in with nocd, each with a deferred atinit that sets a marker, then asserts both markers.

Each defect was reintroduced separately and the matching assertion observed failing:

as"command" deferred atinit did not run: unset      # subscript form restored
nocd deferred atinit did not run: unset             # strip-1 restored

Registered in zsh-n.yml, both path filters and a job. Full suite 24/24.

Note on impact

The silent branch is the more serious of the two. A configuration relying on a deferred atinit hook in an as"command" plug-in has been quietly skipping it, with the load reporting success, so the failure surfaces later as unexplained missing state rather than as an error at load time.

Closes #445