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>

frontend/src/features/tickets/TicketDetail.tsx

@@ -104,6 +104,14 @@ export function TicketDetail({
   const [copied, setCopied] = useState(false);
   // Confirmation shown when the user tries to close with unsaved changes.
   const [confirmClose, setConfirmClose] = useState(false);
+  // Confirmation shown before deleting the ticket (#6).
+  const [confirmDelete, setConfirmDelete] = useState(false);
+
+  // The ticket was deleted (by this view or another actor): close the surface.
+  // The removal from lists flows from the same `issueDeleted` event (#6).
+  useEffect(() => {
+    if (vm.deleted) onClose();
+  }, [vm.deleted, onClose]);
 
   const reloadCount = vm.reloadCount;
   const seededReload = useRef(-1);
@@ -205,6 +213,16 @@ export function TicketDetail({
           >
             {copied ? "Copied" : "Delegation context"}
           </Button>
+          <Button
+            size="sm"
+            variant="ghost"
+            disabled={!t || vm.busy}
+            onClick={() => setConfirmDelete(true)}
+            className="text-danger hover:text-danger"
+            title="Supprimer définitivement ce ticket"
+          >
+            Supprimer
+          </Button>
           <Button size="sm" variant="ghost" onClick={requestClose}>
             Close
           </Button>
@@ -559,6 +577,52 @@ export function TicketDetail({
           </div>
         </div>
       )}
+
+      {/* ── Delete confirmation (#6) ── */}
+      {confirmDelete && (
+        <div
+          role="dialog"
+          aria-modal="true"
+          aria-label="confirmer la suppression"
+          className="fixed inset-0 z-[60] flex items-center justify-center bg-black/55 p-4"
+        >
+          <div className="w-full max-w-sm rounded-lg border border-border bg-surface p-5 shadow-xl">
+            <h4 className="text-sm font-semibold text-content">
+              Supprimer le ticket
+            </h4>
+            <p className="mt-2 text-sm text-muted">
+              Supprimer définitivement le ticket&nbsp;{ticketRef}&nbsp;? Cette
+              action est irréversible.
+            </p>
+            <div className="mt-4 flex flex-wrap items-center justify-end gap-2">
+              <Button
+                size="sm"
+                variant="ghost"
+                aria-label="cancel delete"
+                disabled={vm.busy}
+                onClick={() => setConfirmDelete(false)}
+              >
+                Annuler
+              </Button>
+              <Button
+                size="sm"
+                variant="danger"
+                aria-label="confirm delete"
+                loading={vm.busy}
+                disabled={vm.busy}
+                onClick={async () => {
+                  const ok = await vm.remove();
+                  // On success the surface closes via the `issueDeleted` event
+                  // (the `deleted` flag → onClose effect); just drop the dialog.
+                  if (ok) setConfirmDelete(false);
+                }}
+              >
+                Supprimer
+              </Button>
+            </div>
+          </div>
+        </div>
+      )}
     </div>
   );
 }

frontend/src/features/tickets/tickets.test.tsx

@@ -14,7 +14,7 @@ import {
   MockSystemGateway,
   MockTicketGateway,
 } from "@/adapters/mock";
-import type { Agent } from "@/domain";
+import type { Agent, DomainEvent } from "@/domain";
 import type { Gateways } from "@/ports";
 import { TicketsView } from "./TicketsView";
 import { TicketDetail } from "./TicketDetail";
@@ -108,6 +108,34 @@ describe("MockTicketGateway", () => {
     ).rejects.toMatchObject({ message: expect.stringContaining("version conflict") });
   });
 
+  it("deletes a ticket, removing it and emitting issueDeleted with freedSprint (#6)", async () => {
+    ticket._seedSprint(PROJECT_ID, { id: "s1", order: 1, name: "S" });
+    const t = await ticket.create(PROJECT_ID, { title: "Doomed" });
+    await ticket.setTicketSprint(PROJECT_ID, t.ref, "s1", t.version);
+    const events: DomainEvent[] = [];
+    await system.onDomainEvent((e) => events.push(e));
+
+    await ticket.delete(PROJECT_ID, t.ref);
+
+    // Removed from the store (NotFound afterwards)…
+    await expect(ticket.read(PROJECT_ID, t.ref)).rejects.toMatchObject({
+      code: "NOT_FOUND",
+    });
+    // …and the sprint it was released from is reported on the event.
+    expect(events).toContainEqual({
+      type: "issueDeleted",
+      projectId: PROJECT_ID,
+      issueRef: t.ref,
+      freedSprint: "s1",
+    });
+  });
+
+  it("rejects deleting an unknown ticket with NotFound (#6)", async () => {
+    await expect(ticket.delete(PROJECT_ID, "#404")).rejects.toMatchObject({
+      code: "NOT_FOUND",
+    });
+  });
+
   it("links and unlinks tickets, bumping the version", async () => {
     const a = await ticket.create(PROJECT_ID, { title: "a" });
     await ticket.create(PROJECT_ID, { title: "b" });
@@ -425,6 +453,69 @@ describe("TicketsView", () => {
     ).toBeNull();
   });
 
+  it("deletes a ticket from the detail: confirmation ⇒ row gone + detail closed (#6)", async () => {
+    const t = await ticket.create(PROJECT_ID, { title: "Deletable" });
+    renderView(ticket, system, agent);
+
+    fireEvent.click(await screen.findByText("Deletable"));
+    const detail = await screen.findByRole("dialog", {
+      name: `ticket ${t.ref}`,
+    });
+
+    // Open the confirmation, then confirm the deletion.
+    fireEvent.click(within(detail).getByText("Supprimer"));
+    const confirm = await screen.findByRole("dialog", {
+      name: "confirmer la suppression",
+    });
+    fireEvent.click(within(confirm).getByLabelText("confirm delete"));
+
+    // The gateway removed the ticket…
+    await waitFor(() =>
+      expect(ticket.read(PROJECT_ID, t.ref)).rejects.toMatchObject({
+        code: "NOT_FOUND",
+      }),
+    );
+    // …the detail closed (via the `issueDeleted` event → `deleted` flag)…
+    await waitFor(() =>
+      expect(
+        screen.queryByRole("dialog", { name: `ticket ${t.ref}` }),
+      ).toBeNull(),
+    );
+    // …and the row disappeared from the list (event-driven refresh).
+    await waitFor(() => expect(screen.queryByText("Deletable")).toBeNull());
+    expect(await screen.findByText("No tickets.")).toBeTruthy();
+  });
+
+  it("cancelling the delete confirmation keeps the ticket (#6)", async () => {
+    const t = await ticket.create(PROJECT_ID, { title: "Keeper" });
+    const delSpy = vi.spyOn(ticket, "delete");
+    renderView(ticket, system, agent);
+
+    fireEvent.click(await screen.findByText("Keeper"));
+    const detail = await screen.findByRole("dialog", {
+      name: `ticket ${t.ref}`,
+    });
+
+    fireEvent.click(within(detail).getByText("Supprimer"));
+    const confirm = await screen.findByRole("dialog", {
+      name: "confirmer la suppression",
+    });
+    fireEvent.click(within(confirm).getByLabelText("cancel delete"));
+
+    // The confirmation is dismissed, delete was never called, ticket stays.
+    await waitFor(() =>
+      expect(
+        screen.queryByRole("dialog", { name: "confirmer la suppression" }),
+      ).toBeNull(),
+    );
+    expect(delSpy).not.toHaveBeenCalled();
+    expect(
+      screen.getByRole("dialog", { name: `ticket ${t.ref}` }),
+    ).toBeTruthy();
+    const fresh = await ticket.read(PROJECT_ID, t.ref);
+    expect(fresh.title).toBe("Keeper");
+  });
+
   it("copies a delegation context prompt (F7)", async () => {
     const writeText = stubClipboard();
     const t = await ticket.create(PROJECT_ID, { title: "Delegate me" });

frontend/src/features/tickets/useTicketDetail.ts

@@ -22,6 +22,12 @@ export interface TicketDetailViewModel {
   error: string | null;
   /** Set when the last write lost an optimistic-concurrency race (F3). */
   conflict: boolean;
+  /**
+   * Set once the open ticket has been deleted — by this view or any other actor
+   * (ticket #6). Driven by the `issueDeleted` domain event (single source of
+   * truth); the surface reacts by closing itself.
+   */
+  deleted: boolean;
   busy: boolean;
   /**
    * Monotonic counter bumped **only** when the ticket is (re)loaded from the
@@ -42,6 +48,12 @@ export interface TicketDetailViewModel {
   link: (targetRef: string, kind: TicketLinkKind) => Promise<boolean>;
   unlink: (targetRef: string, kind?: TicketLinkKind) => Promise<boolean>;
   assign: (agentId: string, assigned: boolean) => Promise<boolean>;
+  /**
+   * Deletes this ticket (ticket #6). Returns `true` on success. The removal from
+   * lists and the closing of this surface flow from the resulting `issueDeleted`
+   * event (see {@link TicketDetailViewModel.deleted}), not from local mutation.
+   */
+  remove: () => Promise<boolean>;
 }
 
 function describe(e: unknown): string {
@@ -69,6 +81,7 @@ export function useTicketDetail(
   const [ticket, setTicket] = useState<Ticket | null>(null);
   const [error, setError] = useState<string | null>(null);
   const [conflict, setConflict] = useState(false);
+  const [deleted, setDeleted] = useState(false);
   const [busy, setBusy] = useState(false);
   const [reloadCount, setReloadCount] = useState(0);
 
@@ -101,6 +114,12 @@ export function useTicketDetail(
     let cancelled = false;
     void system
       .onDomainEvent((event) => {
+        if (event.type === "issueDeleted" && event.issueRef === ref) {
+          // The open ticket was deleted (here or elsewhere): don't refresh (it
+          // would 404) — flag it so the surface closes (#6).
+          setDeleted(true);
+          return;
+        }
         if (isTicketEvent(event) && event.issueRef === ref) void refresh();
       })
       .then((u) => {
@@ -186,10 +205,27 @@ export function useTicketDetail(
     [run, gateway, projectId, ref],
   );
 
+  const remove: TicketDetailViewModel["remove"] = useCallback(async () => {
+    setBusy(true);
+    setError(null);
+    try {
+      await gateway.delete(projectId, ref);
+      // Closing/removal flows from the `issueDeleted` event (single source of
+      // truth) — see the `deleted` flag set in the subscription above.
+      return true;
+    } catch (e) {
+      setError(describe(e));
+      return false;
+    } finally {
+      setBusy(false);
+    }
+  }, [gateway, projectId, ref]);
+
   return {
     ticket,
     error,
     conflict,
+    deleted,
     busy,
     reloadCount,
     refresh,
@@ -198,5 +234,6 @@ export function useTicketDetail(
     link,
     unlink,
     assign,
+    remove,
   };
 }