fix(issues): polish sub-issue UI and sync parent children cache

- Add Linear-style "Sub-issue of …" breadcrumb under the title with a
  parent progress ring
- Refresh sub-issues section: progress ring badge, identifier column,
  bordered list, collapse toggle, dashed assignee placeholder
- useUpdateIssue + onIssueUpdated WS handler now also patch and
  invalidate the parent's children query so sub-issue status/assignee
  changes show up on the parent page without a refresh

LICENSE

@@ -1,44 +1,199 @@
-# Open Source License
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
 
-Multica is licensed under a modified version of the Apache License 2.0, with the following additional conditions:
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
 
-1. Multica may be utilized commercially, including as a backend service for
-   other applications or as a task management platform for enterprises.
-   Should the conditions below be met, a commercial license must be obtained
-   from the producer:
+   1. Definitions.
 
-   a. Hosted or embedded service: Unless explicitly authorized by Multica
-      in writing, you may not use the Multica source code to provide a
-      hosted service to third parties, or embed Multica as a component of
-      a product or service that is sold, licensed, or otherwise
-      commercially distributed to third parties.
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
 
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apps/web/features/issues/components/issue-detail.tsx

@@ -256,6 +256,7 @@ export function IssueDetail({ issueId, onDelete, defaultSidebarOpen = true, layo
   const [propertiesOpen, setPropertiesOpen] = useState(true);
   const [detailsOpen, setDetailsOpen] = useState(true);
   const scrollContainerRef = useRef<HTMLDivElement>(null);
+  const [showScrollBottom, setShowScrollBottom] = useState(false);
   const [highlightedId, setHighlightedId] = useState<string | null>(null);
   const didHighlightRef = useRef<string | null>(null);
 
@@ -317,6 +318,23 @@ export function IssueDetail({ issueId, onDelete, defaultSidebarOpen = true, layo
     }
   }, [highlightCommentId, timeline.length]);
 
+  // Track scroll position for jump-to-bottom button
+  useEffect(() => {
+    const container = scrollContainerRef.current;
+    if (!container) return;
+    const onScroll = () => {
+      const { scrollTop, scrollHeight, clientHeight } = container;
+      setShowScrollBottom(scrollHeight - scrollTop - clientHeight > 200);
+    };
+    container.addEventListener("scroll", onScroll, { passive: true });
+    onScroll();
+    return () => container.removeEventListener("scroll", onScroll);
+  }, []);
+
+  const scrollToBottom = useCallback(() => {
+    scrollContainerRef.current?.scrollTo({ top: scrollContainerRef.current.scrollHeight, behavior: "smooth" });
+  }, []);
+
   // Issue field updates via TQ mutation (optimistic update + rollback in mutation hook)
   const updateIssueMutation = useUpdateIssue();
   const handleUpdateField = useCallback(
@@ -762,23 +780,6 @@ export function IssueDetail({ issueId, onDelete, defaultSidebarOpen = true, layo
           </div>
 
           {/* Sub-issues — Linear-style */}
-          {childIssues.length === 0 && (
-            <div className="mt-6">
-              <button
-                type="button"
-                className="inline-flex items-center gap-1.5 text-xs text-muted-foreground hover:text-foreground transition-colors"
-                onClick={() =>
-                  useModalStore.getState().open("create-issue", {
-                    parent_issue_id: issue.id,
-                    parent_issue_identifier: issue.identifier,
-                  })
-                }
-              >
-                <Plus className="h-3.5 w-3.5" />
-                <span>Add sub-issues</span>
-              </button>
-            </div>
-          )}
           {childIssues.length > 0 && (() => {
             const doneCount = childIssues.filter((c) => c.status === "done").length;
             return (
@@ -1123,6 +1124,20 @@ export function IssueDetail({ issueId, onDelete, defaultSidebarOpen = true, layo
             </div>
           </div>
         </div>
+        {/* Jump to bottom button */}
+        {showScrollBottom && (
+          <div className="sticky bottom-4 flex justify-center pointer-events-none">
+            <Button
+              variant="secondary"
+              size="sm"
+              className="pointer-events-auto shadow-md"
+              onClick={scrollToBottom}
+            >
+              <ChevronDown className="mr-1 h-3.5 w-3.5" />
+              Jump to bottom
+            </Button>
+          </div>
+        )}
         </div>
       </div>
       </ResizablePanel>

apps/web/features/landing/i18n/en.ts

@@ -272,24 +272,6 @@ export const en: LandingDict = {
     title: "Changelog",
     subtitle: "New updates and improvements to Multica.",
     entries: [
-      {
-        version: "0.1.9",
-        date: "2026-04-08",
-        title: "Sub-Issues, TanStack Query & Usage Tracking",
-        changes: [
-          "Sub-issue support — create, view, and manage child issues within any issue",
-          "Full migration to TanStack Query for server state (issues, inbox, workspace, runtimes)",
-          "Per-task token usage tracking across all agent providers",
-          "Multiple agents can now run concurrently on the same issue",
-          "Board view: Done column shows total count with infinite scroll",
-          "ReadonlyContent component for lightweight Markdown display in comments",
-          "Optimistic UI updates for reactions and mutations with rollback",
-          "WebSocket-driven cache invalidation replaces polling and refetch-on-focus",
-          "Browser session persists during CLI login flow",
-          "Daemon reuses existing worktrees by updating to latest remote",
-          "Fixed slow tab switching caused by dynamic root layout",
-        ],
-      },
       {
         version: "0.1.8",
         date: "2026-04-07",

apps/web/features/landing/i18n/zh.ts

@@ -272,24 +272,6 @@ export const zh: LandingDict = {
     title: "\u66f4\u65b0\u65e5\u5fd7",
     subtitle: "Multica \u7684\u6700\u65b0\u66f4\u65b0\u548c\u6539\u8fdb\u3002",
     entries: [
-      {
-        version: "0.1.9",
-        date: "2026-04-08",
-        title: "子 Issue、TanStack Query 与用量追踪",
-        changes: [
-          "子 Issue 支持——在任意 Issue 内创建、查看和管理子任务",
-          "全面迁移至 TanStack Query 管理服务端状态（Issue、收件箱、工作区、运行时）",
-          "按任务维度追踪所有 Agent 提供商的 token 用量",
-          "同一 Issue 支持多个 Agent 并发执行",
-          "看板视图：Done 列显示总数并支持无限滚动",
-          "新增 ReadonlyContent 组件，轻量渲染评论中的 Markdown",
-          "表情反应和变更操作支持乐观更新与回滚",
-          "WebSocket 驱动缓存失效，替代轮询和焦点刷新",
-          "CLI 登录流程中浏览器会话保持不丢失",
-          "守护进程复用已有 worktree 时自动拉取最新远程代码",
-          "修复动态根布局导致的标签页切换卡顿问题",
-        ],
-      },
       {
         version: "0.1.8",
         date: "2026-04-07",