feat(occupation): P15 补齐货郎/书生各 2 条每日任务模板 + 既有事件通道信号桥（Kernel 纯函数 TDD）

- TaskTemplateId 扩出 BuyGoods(收货)/Resell(转卖)/ObserveNotes(观察记事)/ReasonDebate(论理)，
  taskPoolOf 货郎=[收货,转卖]、书生=[观察记事,论理]，四职业池均非空。
- TaskSignal 增 Purchased(玩家买入)/Observed(观察)，satisfiesCompletion 给出四模板完成判定；
  新增 occupationSeedOf/refreshToday（跨日才重生成，同日含 Done/Failed 终态保留）。
- signalOfInteraction/advanceTask：仅 playerId 发起的 DialogueEvent/TradeEvent 产生信号，
  NPC 互动不派任务；Offered 须先 acceptTask，终态不可复活。WorldSave 模板 token 双向同步。
- 测试 83 全绿（新增 6：池非空、货郎书生逐日池内确定、模板中文名、完成信号正负、
  事件桥含玩家买/卖与 NPC 忽略、既有 DialogueEvent→accept→Done 全链路、refreshToday 逐日）。
- 不动 Sim.step 数值路径；旧档 v3 模板 token 仅新增合法值，未知模板仍拒绝。

1 files changed, 8 insertions, 0 deletions

diff --git a/src/LivingVillage.Kernel/WorldSave.fs b/src/LivingVillage.Kernel/WorldSave.fs
index 1ce1dcb..b327c6d 100644
--- a/src/LivingVillage.Kernel/WorldSave.fs
+++ b/src/LivingVillage.Kernel/WorldSave.fs
@@ -415,6 +415,10 @@ module WorldSave =
         | Occupation.NightCatch -> add tokens "night-catch"
         | Occupation.SellFish -> add tokens "sell-fish"
         | Occupation.MarketInquiry -> add tokens "market-inquiry"
+        | Occupation.BuyGoods -> add tokens "buy-goods"
+        | Occupation.Resell -> add tokens "resell"
+        | Occupation.ObserveNotes -> add tokens "observe-notes"
+        | Occupation.ReasonDebate -> add tokens "reason-debate"
 
     let private readTaskTemplateId (reader: TokenReader) label =
         match reader.Take(label) with
@@ -424,6 +428,10 @@ module WorldSave =
         | "night-catch" -> Occupation.NightCatch
         | "sell-fish" -> Occupation.SellFish
         | "market-inquiry" -> Occupation.MarketInquiry
+        | "buy-goods" -> Occupation.BuyGoods
+        | "resell" -> Occupation.Resell
+        | "observe-notes" -> Occupation.ObserveNotes
+        | "reason-debate" -> Occupation.ReasonDebate
         | _ -> invalid (sprintf "invalid %s" label)
 
     let private writeTaskState tokens state =