Add diagram delete support

src/main/java/net/sourceforge/plantuml/servlet/DiagramStorageServlet.java

@@ -118,7 +118,31 @@ public class DiagramStorageServlet extends HttpServlet {
         final HttpServletRequest req,
         final HttpServletResponse resp
     ) throws ServletException, IOException {
-        writeError(resp, HttpServletResponse.SC_METHOD_NOT_ALLOWED, "Delete is disabled");
+        if (!isAuthorized(req)) {
+            writeError(resp, HttpServletResponse.SC_UNAUTHORIZED, "Missing or invalid token");
+            return;
+        }
+        final String id = extractId(req);
+        if (id == null || id.isBlank()) {
+            writeError(resp, HttpServletResponse.SC_BAD_REQUEST, "Diagram id is required");
+            return;
+        }
+        if (!storage.isValidId(id)) {
+            writeError(resp, HttpServletResponse.SC_BAD_REQUEST, "Invalid diagram id");
+            return;
+        }
+        final boolean deleted;
+        try {
+            deleted = storage.delete(id);
+        } catch (IOException e) {
+            writeError(resp, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Unable to delete diagram");
+            return;
+        }
+        if (!deleted) {
+            writeError(resp, HttpServletResponse.SC_NOT_FOUND, "Diagram not found");
+            return;
+        }
+        writeJson(resp, HttpServletResponse.SC_OK, Map.of("id", id, "deleted", true));
     }
 
     private String extractId(final HttpServletRequest req) {

src/main/webapp/components/modals/diagram-storage/diagram-storage.jsp

@@ -17,6 +17,7 @@
         <div class="actions-row">
           <input id="diagram-storage-save" class="ok" type="button" value="Sauvegarder" />
           <input id="diagram-storage-load" type="button" value="Charger" />
+          <input id="diagram-storage-delete" class="cancel" type="button" value="Supprimer" />
           <input id="diagram-storage-refresh" type="button" value="Rafraichir la liste" />
         </div>
         <p id="diagram-storage-status" class="status-message"></p>

src/main/webapp/js/storage.js

@@ -280,6 +280,48 @@
       });
   }
 
+  function deleteDiagram(pathValue) {
+    log("delete click", pathValue || dom.path.value);
+    const path = validatePath(pathValue || dom.path.value);
+    if (!path) {
+      return;
+    }
+    const confirmMessage = `Supprimer le diagramme "${path}" ?`;
+    if (!window.confirm(confirmMessage)) {
+      return;
+    }
+    if (dom.del) {
+      dom.del.disabled = true;
+    }
+    const headers = authHeaders({});
+    fetch(`${API_BASE}/${encodeURIComponent(path)}`, { method: "DELETE", headers })
+      .then(handleResponse)
+      .then(() => {
+        setStatus(`Diagramme "${path}" supprime.`, "success");
+        if (dom.path) {
+          dom.path.value = "";
+        }
+        if (dom.name) {
+          dom.name.value = "";
+        }
+        refreshList();
+        closeModal("diagram-storage");
+      })
+      .catch(err => {
+        if (err.status === 401) {
+          setToken();
+        } else {
+          setStatus(`Echec de la suppression : ${err.message}`, "error");
+          console.error("[diagram-storage] delete error", err);
+        }
+      })
+      .finally(() => {
+        if (dom.del) {
+          dom.del.disabled = false;
+        }
+      });
+  }
+
   function bindMenuButtons() {
     const candidates = [
       { id: "menu-item-editor-save", label: "menu save click" },
@@ -326,7 +368,10 @@
       dom.load.addEventListener("click", () => loadDiagram());
     }
     if (dom.del) {
-      dom.del.addEventListener("click", () => {});
+      const freshDelete = dom.del.cloneNode(true);
+      dom.del.parentNode.replaceChild(freshDelete, dom.del);
+      dom.del = freshDelete;
+      dom.del.addEventListener("click", () => deleteDiagram());
     }
     if (dom.refresh) {
       dom.refresh.addEventListener("click", () => refreshList(true));