fix: 侧边详情显示产品/项目/版本上下文

所有 Drawer 新增 contextLabel 可选属性：
- 从工作台打开时传入"产品 / 项目 / 版本"路径
- 显示在 Drawer 顶部灰色背景条中
- 从版本详情打开时不传，不显示（无需冗余）
- 统一样式：px-5 py-2 bg-[var(--bg-subtle)] text-[11px]

涉及组件：
- PlanDetailDrawer
- DevTaskDetailDrawer
- TestCaseDetailDrawer
- BugDetailDrawer

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web/components/bug/BugDetailDrawer.tsx

@@ -21,9 +21,10 @@ const LOG_ACTION_LABEL: Record<string, string> = {
 interface Props {
   bugId: string;
   onClose: () => void;
+  contextLabel?: string;
 }
 
-export function BugDetailDrawer({ bugId, onClose }: Props) {
+export function BugDetailDrawer({ bugId, onClose, contextLabel }: Props) {
   const { bugs, changeStatus, transferBug } = useBugStore();
   const { testCases } = useTestCaseStore();
   const { requirements } = useRequirementStore();
@@ -66,6 +67,11 @@ export function BugDetailDrawer({ bugId, onClose }: Props) {
   return (
     <div className="fixed inset-0 z-50 flex justify-end" onClick={onClose}>
       <div className="w-full max-w-md h-full bg-[var(--bg)] border-l border-[var(--line)] shadow-2xl flex flex-col" onClick={(e) => e.stopPropagation()}>
+        {contextLabel && (
+          <div className="px-5 py-2 border-b border-[var(--line)] bg-[var(--bg-subtle)] shrink-0">
+            <span className="text-[11px] text-[var(--ink-muted)]">{contextLabel}</span>
+          </div>
+        )}
         <div className="flex items-center justify-between h-14 px-5 border-b border-[var(--line)] bg-[var(--bg-card)] shrink-0">
           <div className="flex items-center gap-2">
             <span className="text-[12px] font-mono text-[var(--ink-muted)]">{bug.bugNo}</span>