The list keyboard handler (_onSessionListKeydown) treats Backspace and
Delete as "delete the focused session". When the user double-clicks a
chat to rename it, an <input class="session-rename-input"> is mounted
inside the .list-item row. Backspace on the input bubbles up to the list
container, the handler walks closest('.list-item[data-session-id]') from
e.target, finds the parent row and DELETEs the session via the API —
so a single typo correction nukes the whole conversation.
Bail out at the top of the handler when e.target is an INPUT, TEXTAREA,
or contentEditable element. Arrow / Enter / Delete navigation still
works for rows themselves (the row is the focused element then, not the
input). Mirrors the guard pattern already used in ui.js, notes.js,
tasks.js, calendar.js, emailLibrary.js and galleryEditor.js.
Closes#1007.
