* feat(sessions): first-class archived-session handling
Archived sessions are now exempt from every automatic maintenance path
(age prune, entry cap, model-run prune, disk budget, cleanup repairs);
only explicit sessions.delete removes them. sessions.list gains an
additive tri-state archived filter (true | false | "all"). The sidebar
gets a persisted Active/Archived/All status filter with inline dimmed
archived rows, replacing the nav-away View-archived button; the Sessions
page toggle becomes the same tri-state with dimmed+badged rows in All
mode; the chat composer's archived notice becomes a full-width banner
with an Unarchive action.
* chore(protocol): regenerate Swift gateway models for tri-state archived filter
d4f19bfd79
