fix(runtime): stop/restart d'agent visible robuste — kill réel, état stopped, relance froide (#196, QA verte)

Solidifie le cycle stop/restart d'un agent visible en cellule:

- terminal/registry: kill effectif de la TUI native et de la CLI custom, arrêt idempotent du live runtime (PTY + structuré), distinction nette « agent stoppé » vs « pas de session ».

- workstate + lifecycle: projection d'un état runtime explicite « stopped » (AgentRuntimeState: running/stopping/stopped/failedStart), réconcilié avec le live state; traitement des courses « agent not found ».

- relance froide via freshStart: repart de zéro sans réattacher une session morte et recharge la configuration courante de l'agent (y compris changement de modèle).

- contrat projeté côté adapters frontend (ports/domain/normalization/mock) pour la consommation UI future (#197/#198), sans surface UI ici.

Tests QA verts: workstate_actions, orchestrator_service stop_agent, agent_lifecycle (reopen/fresh_start), workstate stopped runtime state, vitest adapter stop_live_agent.

crates/backend/src/dto.rs

@@ -15,8 +15,9 @@ use application::{
     ConversationPreviewStatus, ConversationTurnWorkPreview, ConversationWorkSummary,
     CreateProjectInput, CreateProjectOutput, ExecuteSlashCommandOutput, GitGraphOutput,
     HealthInput, HealthReport, LayoutKind, ListProjectsOutput, ListSlashCommandsOutput,
-    LiveSessionKind, LiveSessionSnapshot, OpenProjectOutput, ProjectWorkState, SlashCommandEffect,
-    StopLiveAgentOutput, TicketWorkSource, TicketWorkStatus, TurnPage, TurnSource, TurnView,
+    LiveRuntimeState, LiveSessionKind, LiveSessionSnapshot, OpenProjectOutput, ProjectWorkState,
+    SlashCommandEffect, StopLiveAgentOutput, TicketWorkSource, TicketWorkStatus, TurnPage,
+    TurnSource, TurnView,
 };
 use domain::ports::{ReplyProgress, ReplyProgressKind, ReplyProgressSource, ReplyProgressStage};
 use domain::{
@@ -2962,6 +2963,10 @@ pub struct LaunchAgentRequestDto {
     /// view sends `"chat"` to require a structured/headless session.
     #[serde(default)]
     pub cell_kind: Option<CellKind>,
+    /// Cold restart request: ignore any cell conversation id and create a fresh
+    /// provider/CLI conversation after the caller has stopped the previous runtime.
+    #[serde(default)]
+    pub fresh_start: bool,
 }
 
 impl From<LaunchAgentOutput> for TerminalSessionDto {
@@ -3452,6 +3457,8 @@ pub struct LiveAgentDto {
     pub session_id: String,
     /// Runtime family that owns the session (`pty`/`structured`).
     pub kind: LiveWorkSessionKindDto,
+    /// Runtime lifecycle state. Live agents are always `running`.
+    pub runtime_state: LiveRuntimeStateDto,
 }
 
 /// Response DTO for `list_live_agents` (transparent array on the wire).
@@ -3479,6 +3486,7 @@ impl LiveAgentListDto {
                     node_id: snapshot.node_id.to_string(),
                     session_id: snapshot.session_id.to_string(),
                     kind: snapshot.kind.into(),
+                    runtime_state: LiveRuntimeStateDto::Running,
                 })
                 .collect(),
         )
@@ -3504,6 +3512,31 @@ impl From<LiveSessionKind> for LiveWorkSessionKindDto {
     }
 }
 
+/// Explicit lifecycle state for a visible agent runtime.
+#[derive(Debug, Clone, Copy, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub enum LiveRuntimeStateDto {
+    /// A live session exists in one runtime registry.
+    Running,
+    /// A stop request is in progress.
+    Stopping,
+    /// The last live session was torn down.
+    Stopped,
+    /// The last launch attempt failed before registration.
+    FailedStart,
+}
+
+impl From<LiveRuntimeState> for LiveRuntimeStateDto {
+    fn from(state: LiveRuntimeState) -> Self {
+        match state {
+            LiveRuntimeState::Running => Self::Running,
+            LiveRuntimeState::Stopping => Self::Stopping,
+            LiveRuntimeState::Stopped => Self::Stopped,
+            LiveRuntimeState::FailedStart => Self::FailedStart,
+        }
+    }
+}
+
 /// Live session coordinates in the project work-state read model.
 #[derive(Debug, Clone, Serialize)]
 #[serde(rename_all = "camelCase")]
@@ -3514,6 +3547,8 @@ pub struct LiveWorkSessionDto {
     pub session_id: String,
     /// Runtime family that owns the session.
     pub kind: LiveWorkSessionKindDto,
+    /// Runtime lifecycle state. Live sessions are always `running`.
+    pub runtime_state: LiveRuntimeStateDto,
 }
 
 /// Derived processing status of a queued ticket.
@@ -3665,6 +3700,8 @@ pub struct AgentWorkStateDto {
     pub profile_id: String,
     /// Live session, if any.
     pub live: Option<LiveWorkSessionDto>,
+    /// Last known runtime lifecycle state, distinct from live-session presence.
+    pub runtime_state: Option<LiveRuntimeStateDto>,
     /// Current mediated-input busy state.
     pub busy: AgentBusyState,
     /// Pending/in-progress delegation tickets, in FIFO order.
@@ -3789,7 +3826,9 @@ impl From<ProjectWorkState> for ProjectWorkStateDto {
                         node_id: live.node_id.to_string(),
                         session_id: live.session_id.to_string(),
                         kind: live.kind.into(),
+                        runtime_state: LiveRuntimeStateDto::Running,
                     }),
+                    runtime_state: agent.runtime_state.map(Into::into),
                     busy: agent.busy,
                     tickets: agent
                         .tickets
@@ -3976,6 +4015,8 @@ pub struct StopLiveAgentResponseDto {
     pub session_id: String,
     /// Runtime family that owned the session (`pty`/`structured`).
     pub kind: LiveWorkSessionKindDto,
+    /// Runtime lifecycle projection after the stop request.
+    pub runtime_state: LiveRuntimeStateDto,
 }
 
 impl From<StopLiveAgentOutput> for StopLiveAgentResponseDto {
@@ -3984,6 +4025,7 @@ impl From<StopLiveAgentOutput> for StopLiveAgentResponseDto {
             agent_id: out.agent_id.to_string(),
             session_id: out.session_id.to_string(),
             kind: out.kind.into(),
+            runtime_state: out.runtime_state.into(),
         }
     }
 }

crates/backend/src/lib.rs

@@ -730,6 +730,7 @@ impl WakeSessionProvider for AppWakeSessionProvider {
                 mcp_runtime: None,
                 allow_structured_alongside_pty: true,
                 require_structured: false,
+                fresh_start: false,
             })
             .await
             .map_err(|err| WakeError::Session(err.to_string()))?;
@@ -850,6 +851,7 @@ impl AgentResumer for AppAgentResumer {
                 mcp_runtime,
                 allow_structured_alongside_pty: false,
                 require_structured: false,
+                fresh_start: false,
             })
             .await?;