feat(occupation): P11 每日任务生成纯函数 + TaskState 状态机（Kernel 侧）

Occupation.fs 增补：TaskState(Offered|Active|Done|Failed)、TaskTemplateId 首期池=农夫3(送粮/帮工/翻土)+渔夫3(夜捕/卖渔/询价)、DailyTask 记录（设计 §2/§3）。生成 = taskHash(seed ^ occupationSeed, dayIndex) mod |pool|，与 Rng.fs splitmix 同源（禁 System.Random），输出只依赖三元组；taskHash 以 5 个 splitmix 已知向量钉死。完成判定 = satisfiesCompletion 纯谓词，信号 TaskSignal(Dialogued/Traded/ArrivedAt/NightAtWater) 全部来自既有事件通道（DialogueEvent/TradeEvent/到达瓦片/夜+水边），TargetNpc/TargetTile None=通配；acceptTask/applySignal/expireAt 状态机纯函数，Sim.step 数值路径零改动。货郎/书生空池 → dailyTaskOf = None。13 例测试：splitmix 向量、池约束、逐日确定性、窗口=整日、中文名、状态机转移、六模板正负完成信号、终态不可复活、逾期判负。

1 files changed, 118 insertions, 0 deletions

diff --git a/src/LivingVillage.Kernel/Occupation.fs b/src/LivingVillage.Kernel/Occupation.fs
index 28008f5..e0507ae 100644
--- a/src/LivingVillage.Kernel/Occupation.fs
+++ b/src/LivingVillage.Kernel/Occupation.fs
@@ -51,3 +51,121 @@ module Occupation =
 
     let stateOf (kind: Kind) : State =
         { Profile = profileOf kind; TaskToken = 0; StoryStage = 0 }
+
+    // ---- 每日任务（design §3）：Kernel 侧纯函数片，不进 Sim.step 数值路径 ----
+
+    type TaskState =
+        | Offered
+        | Active
+        | Done
+        | Failed
+
+    /// 首期任务池 = 农夫3（送粮/帮工/翻土）+ 渔夫3（夜捕/卖渔/询价），design §3 表。
+    type TaskTemplateId =
+        | DeliverGrain
+        | HelpWork
+        | TillSoil
+        | NightCatch
+        | SellFish
+        | MarketInquiry
+
+    let taskNameOf (template: TaskTemplateId) : string =
+        match template with
+        | DeliverGrain -> "送粮"
+        | HelpWork -> "帮工"
+        | TillSoil -> "翻土"
+        | NightCatch -> "夜捕"
+        | SellFish -> "卖渔"
+        | MarketInquiry -> "询价"
+
+    /// 货郎/书生模板留后续单，当前为空池 → 不生成每日任务。
+    let taskPoolOf (kind: Kind) : TaskTemplateId list =
+        match kind with
+        | Farmer -> [ DeliverGrain; HelpWork; TillSoil ]
+        | Fisher -> [ NightCatch; SellFish; MarketInquiry ]
+        | Peddler
+        | Scholar -> []
+
+    type DailyTask =
+        { TemplateId: TaskTemplateId
+          TargetNpc: Sim.NpcId option
+          TargetTile: (int * int) option
+          OfferedTick: int64
+          DueTick: int64
+          State: TaskState }
+
+    /// 完成判定信号（design §3：走既有事件通道）。
+    /// Dialogued 来自 DialogueEvent（chooseDialogue）；Traded 来自 TradeEvent，
+    /// 字段序 = 卖方/物品/数量（玩家递出即 seller = playerId）；ArrivedAt 为到达瓦片；
+    /// NightAtWater 由调用方把 isNight + 水边判定折叠后喂入。Sim.step 零感知。
+    type TaskSignal =
+        | Dialogued of Sim.NpcId
+        | Traded of Sim.NpcId * Sim.ItemKind * int
+        | ArrivedAt of int * int
+        | NightAtWater
+
+    /// TargetNpc/TargetTile 为 None 时视为通配（指定目标由后续 Desktop 接线单落地）。
+    let satisfiesCompletion (task: DailyTask) (signal: TaskSignal) : bool =
+        match task.TemplateId, signal with
+        | DeliverGrain, Traded (seller, item, quantity) -> seller = Sim.playerId && item = Sim.Food && quantity >= 1
+        | HelpWork, Dialogued npc ->
+            match task.TargetNpc with
+            | Some target -> target = npc
+            | None -> true
+        | TillSoil, ArrivedAt (tileX, tileY) ->
+            match task.TargetTile with
+            | Some target -> target = (tileX, tileY)
+            | None -> true
+        | NightCatch, NightAtWater -> true
+        | SellFish, Traded (seller, item, quantity) -> seller = Sim.playerId && item = Sim.Fish && quantity >= 1
+        | MarketInquiry, Dialogued _ -> true
+        | _ -> false
+
+    /// Offered → Active；其余状态原样返回（终态不可复活）。
+    let acceptTask (task: DailyTask) : DailyTask =
+        if task.State = Offered then { task with State = Active } else task
+
+    /// 仅 Active 下命中完成信号才置 Done；Offered 须先 accept，Done/Failed 终态原样返回。
+    let applySignal (signal: TaskSignal) (task: DailyTask) : DailyTask =
+        if task.State = Active && satisfiesCompletion task signal then
+            { task with State = Done }
+        else
+            task
+
+    /// 逾期判负：DueTick 之后仍未完成 → Failed；Done/Failed 原样返回。
+    let expireAt (nowTick: int64) (task: DailyTask) : DailyTask =
+        if nowTick > task.DueTick && task.State <> Done && task.State <> Failed then
+            { task with State = Failed }
+        else
+            task
+
+    let dayIndexOf (tick: int64) : int64 = tick / Sim.ticksPerDay
+
+    /// hash(seed ^ occupationSeed, dayIndex) —— 与 Rng.fs splitmix 同源（禁 System.Random）。
+    /// 输出只依赖三元组，与调用顺序无关：seed 异或 occupationSeed 后连续推进
+    /// dayIndex+1 次 splitmix，末次输出即当日哈希。
+    let taskHash (seed: uint64) (occupationSeed: uint64) (dayIndex: int64) : uint64 =
+        let mutable state = Rng.ofSeed (seed ^^^ occupationSeed)
+        let mutable out = 0UL
+        if dayIndex >= 0L then
+            for _ in 1L .. dayIndex + 1L do
+                let value, next = Rng.nextUInt64 state
+                out <- value
+                state <- next
+        out
+
+    /// 当日任务生成：池内确定性抽 1 条；空池（货郎/书生首期）→ None。
+    /// TargetNpc/TargetTile 首期留 None（通配），OfferedTick/DueTick 覆盖整日。
+    let dailyTaskOf (seed: uint64) (occupationSeed: uint64) (dayIndex: int64) (kind: Kind) : DailyTask option =
+        match taskPoolOf kind with
+        | [] -> None
+        | pool ->
+            let index = int (taskHash seed occupationSeed dayIndex % uint64 pool.Length)
+            let offered = dayIndex * Sim.ticksPerDay
+            Some
+                { TemplateId = pool.[index]
+                  TargetNpc = None
+                  TargetTile = None
+                  OfferedTick = offered
+                  DueTick = offered + Sim.ticksPerDay - 1L
+                  State = Offered }