fix(Comment): guard against undefined current user in reply delete vi…

[chauquocdung]

Problem

Any comment with a reply becomes invisible to non-admin/manager users.
Comment.vue's reply-delete button check references user.id, but
user is never declared anywhere in the component (no prop, ref,
computed, or store destructure) - it resolves to undefined at runtime.
isCurrentUserAdmin || replyComment.person_id === user.id only crashes
for non-admins, since || short-circuits before user.id is evaluated
for an admin/manager. This is a related gap left by #2168, which added
null-safety to the reply author's avatar but not this separate check.

Solution

Replace user.id with store.state.user.user?.id, the pattern already
used elsewhere in this codebase (e.g. src/lib/init.js) for the current
user's id, with optional chaining for safety.

[frankrousseau]

Thank you @chauquocdung!