fix(push): 删除 push 表中遗留的 app_id 字段

push_device_token 和 push_device_login_log 中存在 NOT NULL 的 app_id 列，
为历史遗留字段（系统已统一使用 appKey），导致 INSERT 时报错 500。
通过 PushSchemaMigrationService 新增迁移删除该字段及对应的旧索引/约束，
并重建 idx_push_device_log_user_time 索引到正确的 app_key 列。

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

push-service/src/main/java/com/xuqm/push/service/PushSchemaMigrationService.java

@@ -36,6 +36,7 @@ public class PushSchemaMigrationService {
         }
 
         migrate_v20260527_create_push_operation_log(emit);
+        migrate_v20260626_remove_app_id(emit);
 
         emit.accept("数据库迁移检查完成");
     }
@@ -79,6 +80,23 @@ public class PushSchemaMigrationService {
         }
     }
 
+    private boolean columnExists(Connection conn, String table, String column) throws SQLException {
+        try (ResultSet rs = conn.getMetaData().getColumns(null, null, table, column)) {
+            return rs.next();
+        }
+    }
+
+    private boolean indexExists(Connection conn, String table, String indexName) throws SQLException {
+        try (ResultSet rs = conn.getMetaData().getIndexInfo(null, null, table, false, false)) {
+            while (rs.next()) {
+                if (indexName.equalsIgnoreCase(rs.getString("INDEX_NAME"))) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
     // ── 各版本迁移 ──────────────────────────────────────────────────────────────
 
     private void migrate_v20260527_create_push_operation_log(Consumer<String> emit) {
@@ -110,4 +128,37 @@ public class PushSchemaMigrationService {
             log.error("migration {} failed", id, e);
         }
     }
+
+    private void migrate_v20260626_remove_app_id(Consumer<String> emit) {
+        final String id = "v20260626_remove_app_id";
+        if (migrationApplied(id)) {
+            emit.accept("[已应用] " + id);
+            return;
+        }
+        try (Connection conn = dataSource.getConnection();
+             Statement stmt = conn.createStatement()) {
+            // push_device_token: remove legacy app_id unique key and column
+            if (columnExists(conn, "push_device_token", "app_id")) {
+                if (indexExists(conn, "push_device_token", "UKj2xmtmdtxgsohtp9c6exx6vl")) {
+                    stmt.execute("ALTER TABLE push_device_token DROP KEY UKj2xmtmdtxgsohtp9c6exx6vl");
+                }
+                stmt.execute("ALTER TABLE push_device_token DROP COLUMN app_id");
+            }
+            // push_device_login_log: rebuild index on app_key, remove app_id column
+            if (columnExists(conn, "push_device_login_log", "app_id")) {
+                if (indexExists(conn, "push_device_login_log", "idx_push_device_log_user_time")) {
+                    stmt.execute("ALTER TABLE push_device_login_log DROP INDEX idx_push_device_log_user_time");
+                }
+                stmt.execute("ALTER TABLE push_device_login_log DROP COLUMN app_id");
+                if (!indexExists(conn, "push_device_login_log", "idx_push_device_log_user_time")) {
+                    stmt.execute("CREATE INDEX idx_push_device_log_user_time ON push_device_login_log (app_key, user_id, created_at)");
+                }
+            }
+            emit.accept("[已迁移] " + id + ": 删除 push 表中遗留 app_id 字段");
+            recordMigration(id, "删除 push_device_token 和 push_device_login_log 中遗留的 app_id 字段");
+        } catch (Exception e) {
+            emit.accept("[错误] " + id + ": " + e.getMessage());
+            log.error("migration {} failed", id, e);
+        }
+    }
 }