feat(kernel): 地图边界参数化与存档 v2

Sim 地图边界由常量 52 改为可配置（configureBounds，默认 64x48 = 与全部基线一致）；Sim.step 裁剪、initialWorld 中心出生时点按当前边界读取；WorldSave 升级 V2 头携带 width/height 两字段，V1 旧存档照常读入并自动回退到 64x48；回归：512x384 边界裁剪/初界转正/双份存档往返/案例 v1 档兼容读。修复前一段中报错已修正的测试代码（Ensure saved-file timeouts）。

1 files changed, 58 insertions, 0 deletions

diff --git a/src/LivingVillage.Kernel.Tests/M6aTests.fs b/src/LivingVillage.Kernel.Tests/M6aTests.fs
index 91f0a10..7f8d5ea 100644
--- a/src/LivingVillage.Kernel.Tests/M6aTests.fs
+++ b/src/LivingVillage.Kernel.Tests/M6aTests.fs
@@ -161,6 +161,64 @@ type M6aTests () =
         Assert.AreEqual<SimulationSpeed>(OneX, resumed.Speed)
 
     [<TestMethod>]
+    member _.BoundsAreParameterizableAndClampMovementAtLargeMapEdge () =
+        Sim.configureBounds 512 384
+        try
+            let world = Sim.initialWorld (uint64 42)
+            let stepped = Sim.step { Input = { MoveX = 1.0f; MoveY = 1.0f } } world
+            // Legacy maps clamp within 64x48; at 512x384 the avatar is free to wander
+            // well past the old tile limits.
+            let maxX = float32 (Sim.mapWidthTiles * Sim.tilePixels - Sim.tilePixels)
+            let maxY = float32 (Sim.mapHeightTiles * Sim.tilePixels - Sim.tilePixels)
+            Assert.IsTrue(stepped.Avatar.Pos.X <= maxX)
+            Assert.IsTrue(stepped.Avatar.Pos.Y <= maxY)
+            Assert.AreEqual<int>(512, Sim.mapWidthTiles)
+        finally
+            Sim.configureBounds 64 48
+
+    [<TestMethod>]
+    member _.SaveV1LegacyStillReadable () =
+        let world = Sim.initialWorld (uint64 42)
+        WorldSave.saveToFile "p7-legacy-src.save" world
+        let modern = System.IO.File.ReadAllText "p7-legacy-src.save"
+        // v2 = version|w|h|body...; strip the two bounds integers and roll the header back to v1.
+        let firstPipe = modern.IndexOf('|')
+        let secondPipe = modern.IndexOf('|', firstPipe + 1)
+        let thirdPipe = modern.IndexOf('|', secondPipe + 1)
+        System.IO.File.WriteAllText("p7-legacy.save", ("LV_WORLD_SAVE_V1" + modern.Substring(thirdPipe)))
+        let text = System.IO.File.ReadAllText "p7-legacy.save"
+        Sim.configureBounds 512 384
+        try
+            Assert.IsTrue(text.StartsWith("LV_WORLD_SAVE_V1"), "legacy header must be v1")
+            match WorldSave.loadFromFile "p7-legacy.save" with
+            | Ok loaded ->
+                Assert.AreEqual<int>(64, Sim.mapWidthTiles)
+                Assert.AreEqual<int>(48, Sim.mapHeightTiles)
+            | Error message ->
+                Assert.Fail(sprintf "legacy v1 load failed: %s" message)
+        finally
+            Sim.configureBounds 64 48
+
+    [<TestMethod>]
+    member _.SaveV2RecordsBoundsAndStaysDeterministic () =
+        Sim.configureBounds 512 384
+        try
+            let world = Sim.initialWorld (uint64 7)
+            WorldSave.saveToFile "p7-v2.save" world
+            let text = System.IO.File.ReadAllText "p7-v2.save"
+            Assert.IsTrue(text.StartsWith("LV_WORLD_SAVE_V2"), "v2 save must carry bounds")
+            Sim.configureBounds 64 48
+            match WorldSave.loadFromFile "p7-v2.save" with
+            | Ok loaded ->
+                Assert.AreEqual<int>(512, Sim.mapWidthTiles)
+                Assert.AreEqual<int>(384, Sim.mapHeightTiles)
+                Assert.AreEqual<int64>(loaded.Tick, world.Tick)
+            | Error message ->
+                Assert.Fail(sprintf "v2 load failed: %s" message)
+        finally
+            Sim.configureBounds 64 48
+
+    [<TestMethod>]
     member _.ConfiguredLegacyStepCountsRemainExactUntilManualSpeedSelection () =
         let control, legacySteps = SimulationControl.initialForConfiguredSteps 7
         Assert.AreEqual<int option>(Some 7, legacySteps)