feat(workstate): read-model live-state minimal des conversations/délégations (Lot A backend)

Introduit le module application `workstate` (modèle de read-model live + snapshots
des conversations/délégations en cours) et l'expose via la couche terminal
(exports mod/registry). Câble la surface Tauri : DTO, commande et state pour
exposer le live-state au frontend (lib + state + commands), avec tests.

QA verte. Réserve environnementale non bloquante : tests loopback socket Unix
réels non exécutables en sandbox (UnixListener::bind PermissionDenied),
alternatives avec skips vertes.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

crates/application/src/workstate/mod.rs

@@ -0,0 +1,124 @@
+//! Read-only project work-state read model.
+//!
+//! This module composes existing runtime state only: the project agent manifest,
+//! live session registries and the input mediator busy state. It performs no I/O
+//! beyond loading the manifest through the existing context store and creates no
+//! durable projection.
+
+use std::collections::HashMap;
+use std::sync::Arc;
+
+use domain::input::AgentBusyState;
+use domain::ports::AgentContextStore;
+use domain::{AgentId, InputMediator, NodeId, ProfileId, Project, SessionId};
+
+use crate::error::AppError;
+use crate::terminal::{LiveSessionKind, LiveSessionSnapshot, LiveSessions};
+
+/// Input for [`GetProjectWorkState::execute`].
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct GetProjectWorkStateInput {
+    /// Project whose manifest provides the agent order and boundary.
+    pub project: Project,
+}
+
+/// Read model for a project's current agent work state.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ProjectWorkState {
+    /// Agents in manifest order.
+    pub agents: Vec<AgentWorkState>,
+}
+
+/// Read model for one manifest agent.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct AgentWorkState {
+    /// Agent id.
+    pub agent_id: AgentId,
+    /// Agent display name.
+    pub name: String,
+    /// Runtime profile id currently assigned to the agent.
+    pub profile_id: ProfileId,
+    /// Current live session, if the agent is live.
+    pub live: Option<LiveWorkSession>,
+    /// Current FIFO/busy state.
+    pub busy: AgentBusyState,
+}
+
+/// Live session coordinates exposed by the work-state read model.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct LiveWorkSession {
+    /// The layout node currently hosting the session view.
+    pub node_id: NodeId,
+    /// The live session id.
+    pub session_id: SessionId,
+    /// Runtime family that owns the session.
+    pub kind: LiveSessionKind,
+}
+
+/// Read-only use case aggregating manifest agents with live and busy state.
+pub struct GetProjectWorkState {
+    contexts: Arc<dyn AgentContextStore>,
+    live: Arc<LiveSessions>,
+    input: Arc<dyn InputMediator>,
+}
+
+impl GetProjectWorkState {
+    /// Builds the read-model use case from existing stores/registries.
+    #[must_use]
+    pub fn new(
+        contexts: Arc<dyn AgentContextStore>,
+        live: Arc<LiveSessions>,
+        input: Arc<dyn InputMediator>,
+    ) -> Self {
+        Self {
+            contexts,
+            live,
+            input,
+        }
+    }
+
+    /// Executes the read-only aggregation.
+    ///
+    /// # Errors
+    /// - [`AppError::Store`] when the manifest cannot be loaded,
+    /// - [`AppError::Invalid`] if a manifest entry violates agent invariants.
+    pub async fn execute(
+        &self,
+        input: GetProjectWorkStateInput,
+    ) -> Result<ProjectWorkState, AppError> {
+        let manifest = self.contexts.load_manifest(&input.project).await?;
+        let live_by_agent = live_by_agent(self.live.live_agent_snapshots());
+        let agents = manifest
+            .entries
+            .iter()
+            .map(|entry| {
+                let agent = entry
+                    .to_agent()
+                    .map_err(|err| AppError::Invalid(err.to_string()))?;
+                let live = live_by_agent
+                    .get(&agent.id)
+                    .map(|snapshot| LiveWorkSession {
+                        node_id: snapshot.node_id,
+                        session_id: snapshot.session_id,
+                        kind: snapshot.kind,
+                    });
+                Ok(AgentWorkState {
+                    agent_id: agent.id,
+                    name: agent.name,
+                    profile_id: agent.profile_id,
+                    live,
+                    busy: self.input.busy_state(agent.id),
+                })
+            })
+            .collect::<Result<Vec<_>, AppError>>()?;
+        Ok(ProjectWorkState { agents })
+    }
+}
+
+fn live_by_agent(snapshots: Vec<LiveSessionSnapshot>) -> HashMap<AgentId, LiveSessionSnapshot> {
+    let mut out = HashMap::new();
+    for snapshot in snapshots {
+        out.entry(snapshot.agent_id).or_insert(snapshot);
+    }
+    out
+}