feat(messaging): add drafts, group compose, templates, reports, blocks, and services

- Add message-draft-list and message-attachments for draft and attachment management

- Add message-group-compose for group messaging

- Add message-template-picker for message templates

- Add message-report-block for reporting and blocking users

- Add message-list-section and message-list-skeleton for list rendering

- Add lib and services directories for messaging utilities and service layer

src/modules/messaging/components/message-compose.tsx

@@ -21,6 +21,7 @@ import {
 } from "@/shared/components/ui/select"
 
 import { deleteMessageDraftAction, saveMessageDraftAction, sendMessageAction } from "../actions"
+import { MessageTemplatePicker } from "./message-template-picker"
 import type { RecipientOption } from "../types"
 
 type FieldErrors = Record<string, string[]>
@@ -52,6 +53,8 @@ export function MessageCompose({
   const [draftId, setDraftId] = useState<string | null>(null)
   const [saveStatus, setSaveStatus] = useState<SaveStatus>("idle")
   const draftIdRef = useRef<string | null>(null)
+  // P0-5: 提交标志位，防止发送成功后自动保存 effect 重新创建草稿
+  const submittedRef = useRef(false)
 
   // Keep draftIdRef in sync so auto-save callback reads the latest value
   useEffect(() => {
@@ -64,13 +67,16 @@ export function MessageCompose({
   }
 
   // 自动保存草稿（防抖 2 秒）
+  // P0-5: 检查 submittedRef，提交后不再触发自动保存
   useEffect(() => {
+    if (submittedRef.current) return
     // 没有内容时不保存
     if (!subject.trim() && !content.trim()) return
 
     let cancelled = false
     const timeout = setTimeout(() => {
       if (cancelled) return
+      if (submittedRef.current) return  // 提交后跳过
       const formData = new FormData()
       const currentDraftId = draftIdRef.current
       if (currentDraftId) formData.set("draftId", currentDraftId)
@@ -83,6 +89,7 @@ export function MessageCompose({
       void saveMessageDraftAction(null, formData)
         .then((res) => {
           if (cancelled) return
+          if (submittedRef.current) return  // 提交后跳过
           if (res.success && res.data) {
             setDraftId(res.data)
             setSaveStatus("saved")
@@ -106,6 +113,8 @@ export function MessageCompose({
       toast.error(t("form.selectRecipient"))
       return
     }
+    // P0-5: 标记已提交，阻止后续自动保存 effect 触发新草稿创建
+    submittedRef.current = true
     formData.set("receiverId", receiverId)
     if (parentMessageId) {
       formData.set("parentMessageId", parentMessageId)
@@ -129,9 +138,12 @@ export function MessageCompose({
           setFieldErrors(res.errors)
         }
         toast.error(res.message || t("messages.sendFailed"))
+        // 提交失败时重置 submittedRef 允许后续自动保存
+        submittedRef.current = false
       }
     } catch {
       toast.error(t("messages.sendFailed"))
+      submittedRef.current = false
     } finally {
       setIsWorking(false)
     }
@@ -232,7 +244,15 @@ export function MessageCompose({
           </div>
 
           <div className="grid gap-2">
-            <Label htmlFor="content">{t("form.content")}</Label>
+            <div className="flex items-center justify-between">
+              <Label htmlFor="content">{t("form.content")}</Label>
+              {/* P2-6: 快捷回复模板插入器 */}
+              <MessageTemplatePicker
+                onInsert={(templateContent) => {
+                  setContent((prev) => (prev ? `${prev}\n\n${templateContent}` : templateContent))
+                }}
+              />
+            </div>
             <Textarea
               id="content"
               name="content"