feat(tickets): suppression d'un ticket (backend + frontend)

Ajoute la suppression complète d'un ticket (#6).

Backend Rust :
- port IssueStore::delete (NotFound si absent) + event IssueDeleted{freed_sprint}
- FsIssueStore::delete : supprime .ideai/tickets/<N>/ et l'index sous lock
- use case DeleteIssue + adaptations des tests sprint/ticket_assistant au port
- commande Tauri ticket_delete + câblage events/state/lib

Frontend :
- gateway delete (ports, adapter ticket + mock, domain)
- useTicketDetail : retrait de la liste et fermeture du détail via event issueDeleted
- intégration TicketDetail + tests

Tests verts : application/issue_usecases (6), infrastructure/issue_store (7),
app-tauri --lib (56), frontend vitest (503), npm run build (exit 0).

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

crates/application/src/lib.rs

@@ -79,11 +79,11 @@ pub use git::{
 pub use health::{HealthInput, HealthReport, HealthUseCase};
 pub use issues::{
     AssignIssueAgent, AssignIssueAgentInput, AssignIssueAgentOutput, CreateIssue, CreateIssueInput,
-    CreateIssueOutput, LinkIssues, LinkIssuesInput, LinkIssuesOutput, ListIssues, ListIssuesInput,
-    ListIssuesOutput, ReadIssue, ReadIssueCarnet, ReadIssueCarnetInput, ReadIssueCarnetOutput,
-    ReadIssueInput, ReadIssueOutput, UnlinkIssues, UnlinkIssuesInput, UpdateIssue,
-    UpdateIssueCarnet, UpdateIssueCarnetInput, UpdateIssueCarnetOutput, UpdateIssueInput,
-    UpdateIssueOutput,
+    CreateIssueOutput, DeleteIssue, DeleteIssueInput, DeleteIssueOutput, LinkIssues,
+    LinkIssuesInput, LinkIssuesOutput, ListIssues, ListIssuesInput, ListIssuesOutput, ReadIssue,
+    ReadIssueCarnet, ReadIssueCarnetInput, ReadIssueCarnetOutput, ReadIssueInput, ReadIssueOutput,
+    UnlinkIssues, UnlinkIssuesInput, UpdateIssue, UpdateIssueCarnet, UpdateIssueCarnetInput,
+    UpdateIssueCarnetOutput, UpdateIssueInput, UpdateIssueOutput,
 };
 pub use layout::{
     CreateLayout, CreateLayoutInput, CreateLayoutOutput, DeleteLayout, DeleteLayoutInput,