fix(processing): clear replay error state

人工重放把 FAILED/DEAD 拨回 PENDING 时，与 attempts/next_attempt_at 一起清空 error_class 与 last_error，使活动状态不携带上一轮失败结论；identity_key、白名单与 MessageLifecycleGate 不变。

同语句同时改 JDBC 与内存实现，避免两套行为漂移。验证：ReplayServiceTest 3/0、InboxLifecycleJdbcSqlTest 8/0（H2 真实 SQL）。

src/test/kotlin/com/gzzn/omms/msgexchange/infra/persistence/jdbc/InboxLifecycleJdbcSqlTest.kt

@@ -142,6 +142,30 @@ class InboxLifecycleJdbcSqlTest {
         assertEquals(InboxCursorRepository.Cursor(42L, t0), cursor.load())
     }
 
+    @Test
+    fun `replay resets attempts, backoff and the previous error reason`() {
+        seed(12L, t0)
+        ds.update(
+            "UPDATE proc_state SET state = 'FAILED', attempts = 4, next_attempt_at = ?, " +
+                "error_class = 'INFRA', last_error = 'boom', identity_key = 'k12' WHERE msg_id = ?",
+            { ps ->
+                ps.setTimestamp(1, Timestamp.from(t0))
+                ps.setLong(2, 12L)
+            },
+        )
+
+        val n = proc.requeueByErrorClasses(listOf(ErrorClass.INFRA))
+
+        assertEquals(1, n)
+        val row = proc.find(12L)!!
+        assertEquals(ProcStatus.PENDING, row.state)
+        assertEquals(0, row.attempts)
+        assertNull(row.nextAttemptAt)
+        assertNull(row.errorClass)   // 重放后不携带上一轮失败结论（design「失败恢复与维护作业」）
+        assertNull(row.lastError)
+        assertEquals("k12", row.identityKey)   // 身份保留，避免重放时把自己判成重复
+    }
+
     @Test
     fun `pipeline transaction rolls back terminal and outbox writes after a late failure`() {
         seed(11L, t0)

src/test/kotlin/com/gzzn/omms/msgexchange/infra/retry/ReplayServiceTest.kt

@@ -11,7 +11,7 @@ import java.time.Instant
 
 /**
  * 人工重放的规矩：只有"可以重放"的失败原因才能把消息从 FAILED / DEAD 拉回队列
- * （重试次数清零，马上再试一次）；报文本身非法的记录永远不允许重放。
+ * （重试次数清零、旧错误原因清空，马上再试一次）；报文本身非法的记录永远不允许重放。
  */
 class ReplayServiceTest {
 
@@ -67,7 +67,10 @@ class ReplayServiceTest {
                 val s = rows[id]!!
                 if (s.errorClass != null && s.errorClass in errorClasses &&
                     (s.state == ProcStatus.FAILED || s.state == ProcStatus.DEAD)) {
-                    rows[id] = s.copy(state = ProcStatus.PENDING, attempts = 0, nextAttemptAt = null)
+                    rows[id] = s.copy(
+                        state = ProcStatus.PENDING, attempts = 0, nextAttemptAt = null,
+                        errorClass = null, lastError = null,
+                    )
                     n++
                 }
             }
@@ -90,6 +93,9 @@ class ReplayServiceTest {
         assertEquals(ProcStatus.PENDING, repo.rows[1]!!.state)
         assertEquals(0, repo.rows[1]!!.attempts)
         assertNull(repo.rows[1]!!.nextAttemptAt)
+        assertNull(repo.rows[1]!!.errorClass)   // 重放后不携带上一轮失败结论
+        assertNull(repo.rows[1]!!.lastError)
+        assertEquals("k1", repo.rows[1]!!.identityKey)   // 身份保留，避免重放时把自己判成重复
         assertEquals(ProcStatus.DEAD, repo.rows[2]!!.state)   // MALFORMED 永不被重放
         assertEquals(ProcStatus.PENDING, repo.rows[3]!!.state)
     }