fix(frontend): persist generation in-flight key in sessionStorage (HMR/reload)

Made-with: Cursor

frontend/src/composables/useGenerationInFlight.js

@@ -1,10 +1,58 @@
 import { ref } from 'vue'
 
+const STORAGE_KEY = 'ma_generation_inflight'
+const STORAGE_TS = 'ma_generation_inflight_ts'
+/** 含 LLM 的重新生成可能较久；超时后视为未进行，避免按钮永久禁用 */
+const TTL_MS = 45 * 60 * 1000
+
+function readPersisted() {
+  if (typeof sessionStorage === 'undefined') return null
+  try {
+    const k = sessionStorage.getItem(STORAGE_KEY)
+    const ts = sessionStorage.getItem(STORAGE_TS)
+    if (!k || ts == null) return null
+    const t = Number(ts)
+    if (!Number.isFinite(t) || Date.now() - t > TTL_MS) {
+      sessionStorage.removeItem(STORAGE_KEY)
+      sessionStorage.removeItem(STORAGE_TS)
+      return null
+    }
+    return k
+  } catch {
+    return null
+  }
+}
+
+function writePersisted(k) {
+  if (typeof sessionStorage === 'undefined') return
+  try {
+    if (k) {
+      sessionStorage.setItem(STORAGE_KEY, k)
+      sessionStorage.setItem(STORAGE_TS, String(Date.now()))
+    } else {
+      sessionStorage.removeItem(STORAGE_KEY)
+      sessionStorage.removeItem(STORAGE_TS)
+    }
+  } catch {
+    /* 隐私模式 / 配额 */
+  }
+}
+
 /**
- * 长耗时生成类 POST/GET 的「进行中」标记（模块级，路由切换不丢）。
+ * 长耗时生成类 POST/GET 的「进行中」标记。
+ * 除模块级 ref 外写入 sessionStorage，避免 Vite HMR / 整页刷新后丢失，
+ * 从而出现「切换页签后重新生成又可点」的假象。
+ *
  * key 示例：`strategy-draft:12`、`regenerate-report:12`、`preview-report:12`
  */
-const inFlightKey = ref(null)
+const inFlightKey = ref(readPersisted())
+
+if (typeof window !== 'undefined') {
+  window.addEventListener('storage', (e) => {
+    if (e.key !== STORAGE_KEY && e.key !== STORAGE_TS) return
+    inFlightKey.value = readPersisted()
+  })
+}
 
 export function generationInFlightKey() {
   return inFlightKey
@@ -17,11 +65,13 @@ export function generationInFlightKey() {
  */
 export async function withGenerationInFlight(key, fn) {
   inFlightKey.value = key
+  writePersisted(key)
   try {
     return await fn()
   } finally {
     if (inFlightKey.value === key) {
       inFlightKey.value = null
+      writePersisted(null)
     }
   }
 }