feat(m4b): 增加可追踪谣言传播与回放

[变更性质]
- 本提交新增 M4b 谣言传播与确定性验收能力，不是单纯缺陷修复。

[新增功能]
- 支持带来源、父节点、深度、强度和路径的谣言传播、去重、衰减与过期处理。
- Headless 支持稳定谣言 dump、replay，以及与 batch 模式的互斥校验。

[实现方案]
- 通过不可变 World 更新和失败原子返回保持模拟确定性。
- 新增多跳传播、重复转述、过期父节点、非法参与者和稳定 trace 测试。

[影响范围]
- 影响 Kernel、Headless 和 Kernel 测试；不包含 M5/M6 或无关配置与文档改动。

1 files changed, 31 insertions, 12 deletions

diff --git a/src/LivingVillage.Headless/Program.fs b/src/LivingVillage.Headless/Program.fs
index bcf2e41..6ba0f5f 100644
--- a/src/LivingVillage.Headless/Program.fs
+++ b/src/LivingVillage.Headless/Program.fs
@@ -164,6 +164,16 @@ let dumpRelations (world: World) : unit =
     printfn "rel_counts %s" (String.concat " " cells)
     printfn "rel_total=%d rel_max=%d rel_min=%d" (Array.sum counts) (Array.max counts) (Array.min counts)
 
+let dumpRumors (world: World) : unit =
+    printfn "%s" (Sim.rumorTraceText world)
+
+let replayRumors (days: int64) (seed: uint64) (npcCount: int) (world: World) : bool =
+    let expected = Sim.rumorTraceText world
+    let replayed = runSimulation false days seed npcCount |> fun stats -> Sim.rumorTraceText stats.World
+    let same = expected = replayed
+    printfn "rumor_replay=%s tick=%d count=%d" (if same then "PASS" else "FAIL") world.Tick world.Rumors.Length
+    same
+
 let gini (xs: int64[]) : float =
     let n = float xs.Length
     let s = float (Array.sum xs)
@@ -266,45 +276,54 @@ let main argv =
         (seed: uint64 option)
         (npc: int option)
         (dump: bool)
+        (rumorTrace: bool)
+        (rumorReplay: bool)
         (batch: (int * int64) option)
-        : Result<int64 * uint64 * int * bool * (int * int64) option, string> =
+        : Result<int64 * uint64 * int * bool * bool * bool * (int * int64) option, string> =
         if i >= argv.Length then
             match batch with
-            | Some(k, d) -> Ok(defaultArg days 1L, defaultArg seed 42UL, defaultArg npc 30, dump, Some(k, d))
+            | Some(k, d) -> Ok(defaultArg days 1L, defaultArg seed 42UL, defaultArg npc 30, dump, rumorTrace, rumorReplay, Some(k, d))
             | None ->
                 match days, seed, npc with
-                | Some d, Some s, Some n -> Ok(d, s, n, dump, None)
+                | Some d, Some s, Some n -> Ok(d, s, n, dump, rumorTrace, rumorReplay, None)
                 | _ -> Error "missing --days/--seed"
         else
             match argv.[i] with
             | "--days" when i + 1 < argv.Length ->
                 (match Int64.TryParse argv.[i + 1] with
-                 | true, d when d > 0L -> parse (i + 2) (Some d) seed npc dump batch
+                 | true, d when d > 0L -> parse (i + 2) (Some d) seed npc dump rumorTrace rumorReplay batch
                  | _ -> Error $"invalid --days '{argv.[i + 1]}'")
             | "--seed" when i + 1 < argv.Length ->
                 (match UInt64.TryParse argv.[i + 1] with
-                 | true, s -> parse (i + 2) days (Some s) npc dump batch
+                 | true, s -> parse (i + 2) days (Some s) npc dump rumorTrace rumorReplay batch
                  | _ -> Error $"invalid --seed '{argv.[i + 1]}'")
             | "--npc" when i + 1 < argv.Length ->
                 (match Int32.TryParse argv.[i + 1] with
-                 | true, n when n > 0 && n <= 1000 -> parse (i + 2) days seed (Some n) dump batch
+                 | true, n when n > 0 && n <= 1000 -> parse (i + 2) days seed (Some n) dump rumorTrace rumorReplay batch
                  | _ -> Error $"invalid --npc '{argv.[i + 1]}'")
-            | "--dump-relations" -> parse (i + 1) days seed npc true batch
+            | "--dump-relations" -> parse (i + 1) days seed npc true rumorTrace rumorReplay batch
+            | "--dump-rumors" -> parse (i + 1) days seed npc dump true rumorReplay batch
+            | "--replay-rumors" -> parse (i + 1) days seed npc dump rumorTrace true batch
             | "--batch" when i + 2 < argv.Length ->
                 (match Int32.TryParse argv.[i + 1], Int64.TryParse argv.[i + 2] with
-                 | (true, k), (true, d) when k > 0 && d > 0L -> parse (i + 3) days seed npc dump (Some(k, d))
+                 | (true, k), (true, d) when k > 0 && d > 0L -> parse (i + 3) days seed npc dump rumorTrace rumorReplay (Some(k, d))
                  | _ -> Error $"invalid --batch '{argv.[i + 1]} {argv.[i + 2]}'")
             | other -> Error $"unknown argument '{other}'"
 
-    match parse 0 None None (Some 30) false None with
-    | Ok(days, seed, npc, dump, batch) ->
+    match parse 0 None None (Some 30) false false false None with
+    | Ok(days, seed, npc, dump, rumorTrace, rumorReplay, batch) ->
         match batch with
+        | Some(k, d) when rumorTrace || rumorReplay ->
+            eprintfn "headless: rumor trace/replay cannot be combined with --batch"
+            2
         | Some(k, d) -> runBatch k d
         | None ->
             let stats = runSimulation true days seed npc
             if dump then dumpRelations stats.World
-            if stats.NonFinite > 0L || stats.OutOfBounds > 0L then 1 else 0
+            if rumorTrace then dumpRumors stats.World
+            let replayOk = if rumorReplay then replayRumors days seed npc stats.World else true
+            if stats.NonFinite > 0L || stats.OutOfBounds > 0L || not replayOk then 1 else 0
     | Error msg ->
         eprintfn $"headless: {msg}"
-        eprintfn "usage: dotnet run -c Release --project src/LivingVillage.Headless -- --days N --seed S [--npc N] [--dump-relations] | --batch K D"
+        eprintfn "usage: dotnet run -c Release --project src/LivingVillage.Headless -- --days N --seed S [--npc N] [--dump-relations] [--dump-rumors] [--replay-rumors] | --batch K D"
         2