fix(domain,application,infrastructure,backend,app-tauri,frontend): Stop demande agent préserve la conversation ouverte — arrêt sans fermeture/clôture du chat, états cohérents après cancel sur les 3 adapters de session, cellule et workstate synchronisés — #343 (QA verte)

crates/backend/src/dto.rs

@@ -12,16 +12,19 @@ use serde_json::Value;
 
 use application::{
     AgentBackgroundTaskState, AgentTicketState, AppError, AppExitWorkGuardDetail,
-    AppExitWorkGuardState, AttachLiveAgentOutput, BackgroundTaskKindLabel, CellAgentPresentation,
-    ConversationPreviewStatus, ConversationTurnWorkPreview, ConversationWorkSummary,
-    CreateProjectInput, CreateProjectOutput, ExecuteSlashCommandOutput, GitGraphOutput,
-    HealthInput, HealthReport, LayoutKind, ListProjectsOutput, ListSlashCommandsOutput,
-    LiveRuntimeState, LiveSessionKind, LiveSessionSnapshot, OpenProjectOutput, ProjectWorkState,
-    RestartCellAgentRuntimeOutput, RestoreOpenProjectFailure, RestoreOpenProjectsOutput,
-    SlashCommandEffect, StopLiveAgentOutput, TicketWorkSource, TicketWorkStatus, TurnPage,
-    TurnSource, TurnView,
+    AppExitWorkGuardState, AttachLiveAgentOutput, BackgroundTaskKindLabel, CancelAgentChatOutput,
+    CellAgentPresentation, ConversationPreviewStatus, ConversationTurnWorkPreview,
+    ConversationWorkSummary, CreateProjectInput, CreateProjectOutput, ExecuteSlashCommandOutput,
+    GitGraphOutput, HealthInput, HealthReport, LayoutKind, ListProjectsOutput,
+    ListSlashCommandsOutput, LiveRuntimeState, LiveSessionKind, LiveSessionSnapshot,
+    OpenProjectOutput, ProjectWorkState, RestartCellAgentRuntimeOutput, RestoreOpenProjectFailure,
+    RestoreOpenProjectsOutput, SlashCommandEffect, StopLiveAgentOutput, TicketWorkSource,
+    TicketWorkStatus, TurnPage, TurnSource, TurnView,
+};
+use domain::ports::{
+    CancelCurrentTurnOutcome, ReplyProgress, ReplyProgressKind, ReplyProgressSource,
+    ReplyProgressStage,
 };
-use domain::ports::{ReplyProgress, ReplyProgressKind, ReplyProgressSource, ReplyProgressStage};
 use domain::{
     AgentBusyState, PageCursor, PageDirection, Project, ProjectId, ProjectSystemPermissions,
     ResolvedAgentSystemPermissions, SlashCommand, SystemPermissionSet, TurnRole,
@@ -4763,6 +4766,45 @@ pub struct StopLiveAgentResponseDto {
     pub already_stopped: bool,
 }
 
+/// Response DTO for a non-destructive `cancel_agent_chat` request.
+#[derive(Debug, Clone, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct CancelAgentChatResponseDto {
+    /// Stable structured session, still live after the operation.
+    pub session_id: String,
+    /// Idempotent turn-level result.
+    pub outcome: CancelAgentChatOutcomeDto,
+}
+
+/// Public cancellation outcomes, distinct from a missing-session error.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub enum CancelAgentChatOutcomeDto {
+    /// A running request was cancelled.
+    Cancelled,
+    /// That request had already been cancelled.
+    AlreadyCancelled,
+    /// The live session currently had no running request.
+    AlreadyCompleted,
+}
+
+impl From<CancelAgentChatOutput> for CancelAgentChatResponseDto {
+    fn from(output: CancelAgentChatOutput) -> Self {
+        Self {
+            session_id: output.session_id.to_string(),
+            outcome: match output.outcome {
+                CancelCurrentTurnOutcome::Cancelled => CancelAgentChatOutcomeDto::Cancelled,
+                CancelCurrentTurnOutcome::AlreadyCancelled => {
+                    CancelAgentChatOutcomeDto::AlreadyCancelled
+                }
+                CancelCurrentTurnOutcome::AlreadyCompleted => {
+                    CancelAgentChatOutcomeDto::AlreadyCompleted
+                }
+            },
+        }
+    }
+}
+
 /// One stopped runtime in an agent-level stop response.
 #[derive(Debug, Clone, Serialize)]
 #[serde(rename_all = "camelCase")]
@@ -6298,6 +6340,22 @@ mod tests {
     use serde_json::json;
     use uuid::Uuid;
 
+    #[test]
+    fn cancel_agent_chat_outcomes_are_stable_camel_case_values() {
+        let response = CancelAgentChatResponseDto::from(CancelAgentChatOutput {
+            session_id: domain::SessionId::from_uuid(Uuid::from_u128(343)),
+            outcome: CancelCurrentTurnOutcome::AlreadyCancelled,
+        });
+
+        assert_eq!(
+            serde_json::to_value(response).unwrap(),
+            json!({
+                "sessionId": Uuid::from_u128(343).to_string(),
+                "outcome": "alreadyCancelled"
+            })
+        );
+    }
+
     #[test]
     fn settings_dtos_are_additive_and_validate_language_and_icon_contracts() {
         let legacy_user: UserSettingsDto = serde_json::from_value(json!({})).unwrap();