Adds a full, non-capped agent terminal reachable from a new expand
trigger on the embedded AgentTermPreview (the detail-panel preview on
AgentsPage stays as-is, just gains the trigger). Opens
/agents/:name/terminal in a new dynamic tab in Shell's header, next to
the static nav row — tabs persist across a reload via useDynamicTabs,
a small localStorage-backed hook built on @hive/shared's existing
settings-storage primitive.
AgentTermPreview gains two new props to support both mounts from one
component: fullHeight (drops the 12em preview cap, fills its page)
and showHeaderBadges (default true — lets a future caller that
already shows turn_state/model/ctx/cost elsewhere suppress this
cluster; AgentsPage doesn't use it, see below).
Deviation from the originally posted plan (issue comment 80596): that
plan proposed AgentsPage's embedded preview pass showHeaderBadges as
false, reasoning the detail panel already duplicates that info.
Checked the actual code before implementing — it doesn't; AgentRow/
AgentTypes.ts carry none of turn_state/model/ctx/cost, and
AgentTermPreview's own floating badges are the only place swarm-ui
shows them. Left the badges visible there instead of shipping a
regression the plan's own stated justification didn't hold up to.
Also fixed a same-tab pub/sub race found by actually rendering a cold
load of /agents/:name/terminal (headless chromium, not just reasoning
about the code): useLocalSetting subscribes inside a useEffect, and
mount effects fire children-before-parents, so a descendant's
mount-time write (AgentTerminalPage registering its own tab) can beat
an ancestor's (Shell's) subscription into existence, leaving Shell's
tab row silently empty on a direct/reload load. Fixed by having
useDynamicTabs re-sync from storage on every location change, not
just on notify() — the fix lives in the new hook itself, not in the
shared settings-storage primitive theme/motion overrides also use.