QUALITY-671: roll up orchestration credit usage in the agent-mode footer

[cephalonaut]

Description

Behind the new FeatureFlag::OrchestrationCreditRollup (dogfood-only) flag, the orchestrator's agent-mode footer now reports the orchestration's combined credit usage — orchestrator plus every locally-loaded descendant child — instead of just the orchestrator's own credits.

The expanded footer's "Credits spent (total)" row shows the rollup total and exposes a click-to-expand per-agent breakdown sorted by credits desc (spawn-order tiebreak). The first five rows render inline; any extra rows are revealed by a "Show N more" link. The collapsed pill uses the same rollup total for its headline number and its "has any usage" suppression check; the (+N) last-block annotation is unchanged. With the flag off, both surfaces render exactly as before.

Specs in this PR: specs/QUALITY-671/PRODUCT.md, specs/QUALITY-671/TECH.md.

Mocks: https://www.figma.com/design/AsF5uAM6L5tUmc11vm9YSi/Agent-orchestration?node-id=4636-32697&m=dev
Screenshots:

Key pieces:

• app/src/ai/blocklist/usage/rollup.rs — pure aggregation helper. Walks descendants via BlocklistAIHistoryModel, filters zero-credit contributors, sorts the breakdown, returns None when nothing applies.
• app/src/ai/blocklist/orchestration_topology.rs — descendant walker lifted out of orchestration_pill_bar.rs so the pill bar and the rollup share one traversal. The pill bar's relevant tests moved to orchestration_topology_tests.rs; avatar helpers (render_orchestrator_avatar_disc, render_agent_avatar_disc) promoted to pub(crate) so the footer rows can reuse them.
• ConversationUsageView — new new_footer_with_rollup constructor subscribes to history events; renders the "View details" / "Hide details" toggle and the per-agent rows. Agent names use the same color as the "USAGE SUMMARY" header; per-agent credit values use the "Credits spent" label color. Names are clipped to the pill bar's max width with ellipsis. Toggles and "Show N more" use the theme's hyperlink color (ansi_fg_blue). A blank value-side placeholder opposite "Show N more" keeps the two-column flex aligned for the rows below.
• BlocklistAIHistoryEvent::ConversationUsageMetadataUpdated — new conversation-scoped event emitted from update_conversation_cost_and_usage_for_request. The footer view and the AIBlock model subscribe so the orchestrator's pill and footer stay live when any descendant spends credits.
• terminal/view.rs::handle_usage_footer_toggled — routes through the rollup-aware constructor when the flag is enabled, and uses add_typed_action_view so the view's TypedActionView handler is actually registered with the framework (without this, the toggle / show-more clicks were silently dropped).
• output.rs::render_usage_button — collapsed pill computes the rollup behind the flag and feeds total_credits into the headline number + suppression check.

Linked Issue

QUALITY-671

Testing

• app/src/ai/blocklist/usage/rollup_tests.rs — 8 unit tests covering the aggregation contract: no-descendants → None, sum + sort across descendants, zero-credit filter, transitive grandchildren, spawn-order tie-break, unloaded-descendant skip, six-contributor truncation precondition, all-zero short-circuit.
• app/src/ai/blocklist/orchestration_topology_tests.rs — tree-walker correctness tests moved over from the pill bar.
• app/src/ai/blocklist/usage/conversation_usage_view_tests.rs — handler-level tests that stand the view up via add_typed_action_view and verify ToggleDetailsExpanded / ShowAllAgentRows flip the right state (regression guard against the original "dispatched action has no handlers" bug).
• cargo fmt --check, cargo clippy --workspace --exclude command-signatures-v2 --all-targets --all-features --tests -- -D warnings, and ./script/presubmit all clean.
• I have manually tested my changes locally with ./script/run

Agent Mode

• Warp Agent Mode - This PR was created via Warp's AI Agent Mode

CHANGELOG-IMPROVEMENT: Roll up child-agent credit usage into the orchestrator's agent-mode footer.

---

Conversation

[oz-for-oss]

@cephalonaut

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[oz-for-oss]

Overview

This PR adds a feature-flagged orchestration credit rollup for the agent-mode footer and collapsed usage pill, with shared topology traversal, aggregation helpers, and footer UI state for the breakdown.

Concerns

• The rollup currently activates when only the orchestrator has credits and all descendants are idle, which contradicts the intended descendant-credit gating and adds a misleading one-row breakdown.
• The new link-style controls are implemented as mouse-only hover/click elements, so the required keyboard activation path for View details and Show N more is missing.

Verdict

Found: 0 critical, 2 important, 0 suggestions

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[oz-for-oss]

⚠️ [IMPORTANT] This only checks whether any agent has credits, so an orchestrator with credits plus idle children returns a rollup and renders a "View details" list containing only the orchestrator. The feature is supposed to stay in the existing self-only UI until at least one loaded descendant has spent credits; track descendant credit contributors separately and return None when that count is zero.

[cephalonaut]

Children don't really remain idle, so not really a big deal.

[oz-for-oss]

⚠️ [IMPORTANT] Hoverable plus .on_click makes the View/Hide details control mouse-only, and the Show N more link below uses the same pattern. Use a focusable/button-style element or add keyboard handling so both controls are reachable in tab order and activatable with Enter/Space as required.

[cephalonaut]

The rest of the usage box is not accessible by keyboard, so going to defer this one.

[advait-m]

Wondering if it's possible to restrict this to certain conversation events rather than any conversation event across the app?

i.e. this type of thing

let parent_id = parent_conversation_id;
ctx.subscribe_to_model(&history_model, move |_, history, event, ctx| {
    let touched_id = match event {
        BlocklistAIHistoryEvent::ConversationUsageMetadataUpdated { conversation_id }
        | BlocklistAIHistoryEvent::RemoveConversation { conversation_id, .. }
        | BlocklistAIHistoryEvent::DeletedConversation { conversation_id, .. } => *conversation_id,
        _ => return,
    };
    // history.read takes (&AppContext, F) — collect the bool before notifying
    // so the immutable borrow ends before ctx.notify() needs &mut.
    let should_notify = history.read(ctx, |h, _| {
        touched_id == parent_id
            || descendant_conversation_ids_in_spawn_order(h, parent_id).contains(&touched_id)
    });
    if should_notify {
        ctx.notify();
    }
});

[cephalonaut]

That's good idea - fixed.

[advait-m]

this looks sweet!