feat(core): EventBus dead-letter + consume_with_retry 辅助函数

- 新增 dead_letter_events 表 + Entity
- consume_with_retry: 幂等检查 + 成功标记 + 失败转入 dead-letter
- insert_dead_letter: 写入失败事件供后续排查和手动重试

crates/erp-server/migration/src/lib.rs

@@ -90,6 +90,7 @@ mod m20260427_000087_audit_logs_hash_chain;
 mod m20260428_000088_rls_policy_strict;
 mod m20260428_000089_blind_indexes;
 mod m20260428_000090_critical_alerts;
+mod m20260428_000091_dead_letter_events;
 
 pub struct Migrator;
 
@@ -187,6 +188,7 @@ impl MigratorTrait for Migrator {
             Box::new(m20260428_000088_rls_policy_strict::Migration),
             Box::new(m20260428_000089_blind_indexes::Migration),
             Box::new(m20260428_000090_critical_alerts::Migration),
+            Box::new(m20260428_000091_dead_letter_events::Migration),
         ]
     }
 }

crates/erp-server/migration/src/m20260428_000091_dead_letter_events.rs

@@ -0,0 +1,76 @@
+use sea_orm_migration::prelude::*;
+
+#[derive(DeriveMigrationName)]
+pub struct Migration;
+
+#[derive(Iden)]
+enum DeadLetterEvent {
+    Table,
+    Id,
+    TenantId,
+    OriginalEventId,
+    EventType,
+    Payload,
+    ConsumerId,
+    Attempts,
+    LastError,
+    CreatedAt,
+    ResolvedAt,
+}
+
+#[async_trait::async_trait]
+impl MigrationTrait for Migration {
+    async fn up(&self, manager: &SchemaManager) -> Result<(), DbErr> {
+        manager
+            .create_table(
+                Table::create()
+                    .table(DeadLetterEvent::Table)
+                    .col(
+                        ColumnDef::new(DeadLetterEvent::Id)
+                            .uuid()
+                            .not_null()
+                            .primary_key()
+                            .default(PgFunc::gen_random_uuid()),
+                    )
+                    .col(ColumnDef::new(DeadLetterEvent::TenantId).uuid())
+                    .col(
+                        ColumnDef::new(DeadLetterEvent::OriginalEventId)
+                            .uuid()
+                            .not_null(),
+                    )
+                    .col(
+                        ColumnDef::new(DeadLetterEvent::EventType)
+                            .string_len(128)
+                            .not_null(),
+                    )
+                    .col(ColumnDef::new(DeadLetterEvent::Payload).json_binary())
+                    .col(
+                        ColumnDef::new(DeadLetterEvent::ConsumerId)
+                            .string_len(128)
+                            .not_null(),
+                    )
+                    .col(
+                        ColumnDef::new(DeadLetterEvent::Attempts)
+                            .integer()
+                            .not_null()
+                            .default(0),
+                    )
+                    .col(ColumnDef::new(DeadLetterEvent::LastError).text())
+                    .col(
+                        ColumnDef::new(DeadLetterEvent::CreatedAt)
+                            .timestamp_with_time_zone()
+                            .not_null()
+                            .default(Expr::current_timestamp()),
+                    )
+                    .col(ColumnDef::new(DeadLetterEvent::ResolvedAt).timestamp_with_time_zone())
+                    .to_owned(),
+            )
+            .await
+    }
+
+    async fn down(&self, manager: &SchemaManager) -> Result<(), DbErr> {
+        manager
+            .drop_table(Table::drop().table(DeadLetterEvent::Table).to_owned())
+            .await
+    }
+}