feat(workstate): actions contrôlées sur le work-state (Lot D backend)

Ajoute un module d'actions contrôlées (`workstate/actions.rs`) côté application
et l'expose via des commandes Tauri : DTO camelCase, câblage commands/state/lib.
Les actions valident leurs invariants avant d'agir sur le read-model.

- application : use cases d'actions contrôlées + intégration au work-state.
- app-tauri : commandes dédiées, DTO et enregistrement dans le handler.

Tests verts : application workstate_actions (7), workstate (21),
app-tauri dto_agents (25), list_live_agents_r0b (5), cargo check OK.

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

crates/application/src/lib.rs

@@ -119,8 +119,9 @@ pub use terminal::{
 };
 pub use window::{MoveTabToNewWindow, MoveTabToNewWindowInput, MoveTabToNewWindowOutput};
 pub use workstate::{
-    AgentTicketState, AgentWorkState, ConversationLogProvider, ConversationPreviewStatus,
-    ConversationTurnWorkPreview, ConversationWorkSummary, GetProjectWorkState,
-    GetProjectWorkStateInput, LiveWorkSession, ProjectWorkState, TicketWorkSource,
+    AgentTicketState, AgentWorkState, AttachLiveAgent, AttachLiveAgentInput, AttachLiveAgentOutput,
+    ConversationLogProvider, ConversationPreviewStatus, ConversationTurnWorkPreview,
+    ConversationWorkSummary, GetProjectWorkState, GetProjectWorkStateInput, LiveWorkSession,
+    ProjectWorkState, StopLiveAgent, StopLiveAgentInput, StopLiveAgentOutput, TicketWorkSource,
     TicketWorkStatus,
 };