Migrate frontend to Svelte 5 runes semantics

frontend/src/components/TaskLogViewer.svelte

@@ -35,7 +35,7 @@
      * @TEST_EDGE api_error -> transitions to Error state and displays retry button
      * @TEST_INVARIANT displays_logs -> verifies: [valid_viewer]
      */
-    import { createEventDispatcher, onDestroy } from "svelte";
+    import { onDestroy } from "svelte";
     import { getTaskLogs } from "../services/taskService.js";
     import { t } from "../lib/i18n";
     import TaskLogPanel from "./tasks/TaskLogPanel.svelte";
@@ -46,10 +46,9 @@
         taskId = null,
         taskStatus = null,
         realTimeLogs = [],
+        onclose = () => {},
     } = $props();
 
-    const dispatch = createEventDispatcher();
-
     let logs = $state([]);
     let loading = $state(false);
     let error = $state("");
@@ -101,11 +100,11 @@
 
     // [DEF:handleFilterChange:Function]
     // @PURPOSE: Updates filter conditions for the log viewer
-    // @PRE: event contains detail with source and level
+    // @PRE: event contains source and level fields
     // @POST: Log viewer filters updated
     function handleFilterChange(event) {
         console.log("[TaskLogViewer][UI][handleFilterChange:START]");
-        const { source, level } = event.detail;
+        const { source, level } = event;
     }
     // [/DEF:handleFilterChange:Function]
 
@@ -177,8 +176,7 @@
                     {taskId}
                     {logs}
                     {autoScroll}
-                    on:filterChange={handleFilterChange}
-                    on:refresh={handleRefresh}
+                    onfilterchange={handleFilterChange}
                 />
             {/if}
         </div>
@@ -203,9 +201,14 @@
                     aria-hidden="true"
                     onclick={() => {
                         show = false;
-                        dispatch("close");
+                        onclose();
+                    }}
+                    onkeydown={(e) => {
+                        if (e.key === "Escape") {
+                            show = false;
+                            onclose();
+                        }
                     }}
-                    onkeydown={(e) => e.key === "Escape" && (show = false)}
                     role="presentation"
                 ></div>
 
@@ -224,7 +227,7 @@
                                 class="text-gray-500 hover:text-gray-300"
                                 onclick={() => {
                                     show = false;
-                                    dispatch("close");
+                                    onclose();
                                 }}
                                 aria-label={$t.common?.close}>✕</button
                             >
@@ -241,7 +244,7 @@
                                     {taskId}
                                     {logs}
                                     {autoScroll}
-                                    on:filterChange={handleFilterChange}
+                                    onfilterchange={handleFilterChange}
                                 />
                             {/if}
                         </div>