feat(workspace,settings): model menu chip in the composer, compact settings panels

The workspace home's composer takes ONE Model chip (ModelMenu: model list
plus Effort) and moves AI Router / Permission / Local-New worktree into the
row under it; Settings drops the General-page cost card and export row,
PricingSettings and the empty states are compacted for settings panels.

client/src/components/AlertsNotifications.tsx

@@ -663,6 +663,7 @@ export function AlertsNotifications() {
               icon={ListChecks}
               title={t("rules.empty")}
               description={ts("alertsHub.rulesEmptyHint")}
+              compact
             />
           ) : (
             <ul className="space-y-2">
@@ -766,6 +767,7 @@ export function AlertsNotifications() {
               icon={unackedOnly ? BellOff : BellRing}
               title={t("feed.emptyTitle")}
               description={unackedOnly ? t("feed.emptyUnacked") : t("feed.emptyDescription")}
+              compact
             />
           ) : (
             <>