ContextBar relocated from a dedicated row above MessageList to inline with
the agent-picker row, filling the space to the right of the picker + plus
button. Always-visible (zero-state when no assistant message has run yet)
via chat.model_context_limit, which GET /api/sessions/:id/chats now
populates from a single getModelContext lookup per session.
ChatContextPopover above the input is removed entirely along with its
useChatContextStats hook (no remaining callers). Color tiers and the
auto-compaction threshold tooltip unchanged.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Walks chat messages newest-first for the latest ctx_used/ctx_max pair.
Color tiers fire against (max - 20k compaction reserve) so the bar warns
amber/orange/red at the same boundaries auto-compaction triggers.
"Context" → "Ctx" at <640px, (NN%) drops at <380px.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
