feat(persistence)!: V1.4.0 退场 legacy 槽位存储，persistNextStates 成为唯一写路径 (ACM2-29 P4)

- V1.4.0 迁移：DROP FLIGHT_SCHD 全部 77 个槽位/里程碑/紧凑航路列（V1.3.0 起
  零写入、P2-2 起零读取）+ 三个与 PK 前缀冗余的 (flid) 单列索引；回退窗口关闭
  （对拍留档：P2-1 FS7 v2 双读差异记录）
- 接口收敛：FlightSchdRepository 删除 upsertSnapshotBatch/upsertIncremental，
  删除废弃 FlightStateRepository 及 Jdbc/Stub 适配器；仓储与装配器删除全部
  legacy flatten/slot/milestone/route 视图代码，ALL_COLUMNS 收敛为无损承载列
- FS7 对拍工具移除 diffDualRead（legacy 槽位基准退场）；diff() 对 legacy
  FLTR JSON 比对保留；FlightStoreDualReadTest 随工具移除
- 测试种子统一走 v2 写路径（support/SeedHelpers），GuardedFlightSchd 简化
- docs/decision-flight-state.md：头部复核入口更新 + 新增 §10 v2 落地终态索引，
  §1–§9 保留为历史记录

验证：MSGX_PG_PORT=5433 真实 PG 全量 100 用例 0 失败 0 跳过；无环境变量
Testcontainers 全新容器 V1.0.0→V1.4.0 迁移链 18/18 全绿

src/test/kotlin/com/gzzn/omms/msgexchange/processing/FlightSchdInvariantTest.kt

@@ -29,6 +29,8 @@ import com.gzzn.omms.msgexchange.infra.stub.StubMsgEvents
 import com.gzzn.omms.msgexchange.infra.stub.StubPipelineTransactionManager
 import com.gzzn.omms.msgexchange.infra.stub.StubProcState
 import com.gzzn.omms.msgexchange.infra.stub.StubReqTrack
+import com.gzzn.omms.msgexchange.support.seedIncremental
+import com.gzzn.omms.msgexchange.support.seedSnapshot
 import org.junit.jupiter.api.AfterEach
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Assertions.assertFalse
@@ -269,10 +271,10 @@ class FlightSchdInvariantTest {
 
         // 1. 增量更新写入一条临时加飞航班 ADFT（FDAY 为 NULL）
         val adftChange = FlightChange(flid = "ADFT_888", fields = mapOf("FLID" to "ADFT_888", "FLTY" to "ADFT"))
-        flightSchd.upsertIncremental(listOf(adftChange))
+        seedIncremental(flightSchd, listOf(adftChange))
 
         // 2. 写入旧代的一条定期计划航班 REG_OLD（FDAY 为 2026-09-07）
-        flightSchd.upsertSnapshotBatch(day, listOf("REG_OLD" to mapOf("FLID" to "REG_OLD", "FLTY" to "REG")))
+        seedSnapshot(flightSchd, day, listOf("REG_OLD" to mapOf("FLID" to "REG_OLD", "FLTY" to "REG")))
         flightSchd.putGenIfVersion(day, 0L, FlightSchdRepository.GenMeta(day, 1L, setOf("REG_OLD")))
 
         // 3. 执行下一轮快照 DNLD，新代仅包含 REG_NEW（REG_OLD 不在新代中，属于待删差集；ADFT 也不在新代中）
@@ -308,11 +310,11 @@ class FlightSchdInvariantTest {
         val dayNew = "2026-09-08"
 
         // 初始属旧代
-        flightSchd.upsertSnapshotBatch(dayOld, listOf("FL_MIG" to mapOf("FLID" to "FL_MIG", "REMC" to "07")))
+        seedSnapshot(flightSchd, dayOld, listOf("FL_MIG" to mapOf("FLID" to "FL_MIG", "REMC" to "07")))
         flightSchd.putGenIfVersion(dayOld, 0L, FlightSchdRepository.GenMeta(dayOld, 1L, setOf("FL_MIG")))
 
         // 随后 09-08 快照写入将 FDAY 更新为 2026-09-08
-        flightSchd.upsertSnapshotBatch(dayNew, listOf("FL_MIG" to mapOf("FLID" to "FL_MIG", "REMC" to "08")))
+        seedSnapshot(flightSchd, dayNew, listOf("FL_MIG" to mapOf("FLID" to "FL_MIG", "REMC" to "08")))
 
         // 此时 09-07 再次执行差删（差集中包含 FL_MIG）
         val deleted = flightSchd.deleteDiffByDay(dayOld, listOf("FL_MIG"))
@@ -334,7 +336,7 @@ class FlightSchdInvariantTest {
             TimeZone.setDefault(TimeZone.getTimeZone(ZoneId.of("Asia/Tokyo")))
 
             val now = Instant.parse("2026-09-07T08:00:00.123456Z")
-            flightSchd.upsertSnapshotBatch("2026-09-07", listOf("TZ_01" to mapOf("FLID" to "TZ_01")), now)
+            seedSnapshot(flightSchd, "2026-09-07", listOf("TZ_01" to mapOf("FLID" to "TZ_01")), now)
             flightSchd.putGenIfVersion("2026-09-07", 0L, FlightSchdRepository.GenMeta("2026-09-07", 1L, setOf("TZ_01")), now)
 
             val gen = flightSchd.getGen("2026-09-07")