Workspace polish: milestone selector, streaming fix, push fix, log quieting

- WorkspaceTaskPanel: add milestone <select> in task detail (PATCH /api/notes/:id),
  replace delete ✕ with trash can SVG icon
- WorkspaceView: scroll to bottom when streaming ends so final message is visible
  without a page refresh
- ToolCallCard: fix search_notes result count (was reading data.total; tool returns
  data.count), so results no longer show "0 found"
- push.py: switch from deprecated WebPusher().send(vapid_private_key=...) to
  webpush() function (pywebpush 2.x API compatibility)
- app.py: downgrade /api/health, /api/chat/status, and static asset requests from
  INFO to DEBUG in after_request logger to reduce log noise at default log level

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/views/WorkspaceView.vue

@@ -79,7 +79,10 @@ watch(
 watch(
   () => chatStore.streaming,
   (s) => {
-    if (!s) processedCount.value = 0;
+    if (!s) {
+      processedCount.value = 0;
+      scrollToBottom();
+    }
   }
 );