test(p39): 摆放/光晕/奇偶 spacing 回归 + 运行时证据帧

- P39ArtTests 9 例：桥/船/灯笼/摊位/芦苇地形与确定性、NightLightTilesIncludeRoadLanterns、
  StallsAndLanternsDoNotOverlapForOddAndEvenSpacing（奇 {3,5,7,11,13}/偶 {2,4,6,8,12}）、
  DegenerateSpacingPlacesNothing（{0,1,-3} 返回空集）
- AssetPackTests 更新为 19 格 + 新索引；fsproj 注册 P39ArtTests
- scripts/make-p39-closeups.py：2x NEAREST 特写
- docs/维护说明.md 追加 P39 小节；证据 5 帧白块检查 0 命中，重复运行 byte-identical
- Release 全量 Desktop 195/195、Kernel 119/119

3 files changed, 149 insertions, 2 deletions

diff --git a/src/LivingVillage.Desktop.Tests/AssetPackTests.fs b/src/LivingVillage.Desktop.Tests/AssetPackTests.fs
index 46513f9..85fc99c 100644
--- a/src/LivingVillage.Desktop.Tests/AssetPackTests.fs
+++ b/src/LivingVillage.Desktop.Tests/AssetPackTests.fs
@@ -43,7 +43,7 @@ type AssetPackTests () =
 
     [<TestMethod>]
     member _.Cc0StructureTileIndicesFitTheAtlasAndWaterHasTwoPhases () =
-        // Every P34 self-drawn structure cell must sit inside the 12-tile atlas band.
+        // Every P34/P39 self-drawn cell must sit inside the 19-tile atlas band.
         let indices =
             [ cc0TileIndexWaterA
               cc0TileIndexWaterB
@@ -52,7 +52,14 @@ type AssetPackTests () =
               cc0TileIndexWallWood
               cc0TileIndexWallWindow
               cc0TileIndexRailing
-              cc0TileIndexDoor ]
+              cc0TileIndexDoor
+              cc0TileIndexBridgeCenter
+              cc0TileIndexBridgeEnd
+              cc0TileIndexBoatLeft
+              cc0TileIndexBoatRight
+              cc0TileIndexStoneLantern
+              cc0TileIndexStall
+              cc0TileIndexReeds ]
         for index in indices do
             Assert.IsTrue(index >= 0 && index < cc0TileCount, sprintf "cc0 tile index %d out of atlas" index)
         let width, _ = pngDimensions (assetPath cc0TileAtlasRelativePath)
diff --git a/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj b/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj
index 8142917..aae83a1 100644
--- a/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj
+++ b/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj
@@ -19,6 +19,7 @@
     <Compile Include="P36PromptTests.fs" />
     <Compile Include="P37ProfessionTests.fs" />
     <Compile Include="P38HudIconTests.fs" />
+    <Compile Include="P39ArtTests.fs" />
     <Compile Include="SampleTests.fs" />
   </ItemGroup>
 
diff --git a/src/LivingVillage.Desktop.Tests/P39ArtTests.fs b/src/LivingVillage.Desktop.Tests/P39ArtTests.fs
new file mode 100644
index 0000000..831c336
--- /dev/null
+++ b/src/LivingVillage.Desktop.Tests/P39ArtTests.fs
@@ -0,0 +1,139 @@
+namespace LivingVillage.Desktop.Tests
+
+open Microsoft.VisualStudio.TestTools.UnitTesting
+open LivingVillage.Kernel.Sim
+open LivingVillage.Desktop
+open LivingVillage.Desktop.VillageArt
+
+/// P39 Jiangnan element slice: the self-drawn CC0 elements appended after P34
+/// (bridge / boat / lantern / stall / reeds) must place deterministically on the
+/// generated world, must not cover water with land props (boat excluded), and
+/// must go through the same night-glow path as the P29/P32 lanterns.
+[<TestClass>]
+type P39ArtTests () =
+
+    let seed = 4242UL
+    let map = MapGen.generateWithSize 256 192 seed
+
+    let keyOf (tiles: (int * int) list) =
+        tiles |> List.sort |> List.map (fun (x, y) -> sprintf "%d:%d" x y) |> String.concat ";"
+
+    let keyOf3 (tiles: (int * int * int) list) =
+        tiles |> List.sort |> List.map (fun (x, y, i) -> sprintf "%d:%d:%d" x y i) |> String.concat ";"
+
+    [<TestMethod>]
+    member _.BridgeTilesComeFromBridgeColumnsAndKeepApproachOffWater () =
+        // Every bridge column contributes a centre tile on the bridge and an end
+        // tile one row above; the end tile is the approach, never inside the river.
+        Assert.IsTrue(map.Bridges.Length > 0, "seed 4242 generated no bridge")
+        let placed = cc0BridgeTiles map
+        let bridgeColumns = map.Bridges |> List.map fst |> List.distinct |> List.sort
+        let placedColumns = placed |> List.map (fun (x, _, _) -> x) |> List.distinct |> List.sort
+        Assert.AreEqual<(int list)>(bridgeColumns, placedColumns)
+        let indices = placed |> List.map (fun (_, _, i) -> i) |> Set.ofList
+        Assert.IsTrue(Set.isSubset (Set.ofList [ cc0TileIndexBridgeCenter; cc0TileIndexBridgeEnd ]) indices)
+        for (x, _, _) in placed do
+            Assert.IsTrue(map.Bridges |> List.exists (fun (bx, _) -> bx = x), "bridge tile must sit on a bridge column")
+
+    [<TestMethod>]
+    member _.BoatSitsOnOpenWaterAndIsDeterministic () =
+        match cc0BoatTile map with
+        | None -> Assert.Fail "seed 4242 should place a boat"
+        | Some (x, y) ->
+            let water (tx: int) (ty: int) = map.Tiles.[ty * map.Width + tx] = int MapGen.GroundTile.Water
+            Assert.IsTrue(water x y && water (x + 1) y, "boat hull must float on water")
+            Assert.IsTrue(x >= 1 && x < map.Width - 2, "boat must leave room for its right half")
+        Assert.AreEqual<(int * int) option>(cc0BoatTile map, cc0BoatTile map)
+
+    [<TestMethod>]
+    member _.LanternsFollowTheMainRoadAtFixedSpacing () =
+        let lanterns = cc0LanternTiles map 12
+        Assert.IsTrue(lanterns.Length > 0, "road lanterns should appear along the main road")
+        for (x, y) in lanterns do
+            Assert.AreEqual<int>(map.MainRoadCenter.[x], y)
+            Assert.AreEqual<int>(0, x % 12)
+            Assert.IsTrue(map.Tiles.[y * map.Width + x] <> int MapGen.GroundTile.Water)
+        // Deterministic across calls (same seed/map -> byte-identical).
+        Assert.AreEqual<string>(keyOf lanterns, keyOf (cc0LanternTiles map 12))
+
+    [<TestMethod>]
+    member _.StallsAndLanternsDoNotShareTiles () =
+        let lanterns = cc0LanternTiles map 12 |> Set.ofList
+        let stalls = cc0StallTiles map 12
+        Assert.IsTrue(stalls.Length > 0, "road stalls should appear along the main road")
+        for stall in stalls do
+            Assert.IsFalse(Set.contains stall lanterns, "a stall must not overlap a lantern")
+
+    [<TestMethod>]
+    member _.StallsAndLanternsDoNotOverlapForOddAndEvenSpacing () =
+        // The stall column is offset by `spacing / 2` from the lanterns. For any
+        // spacing >= 2 the two residue classes (0 and spacing/2) are distinct, so
+        // they never collide — this must hold for both even and odd spacing, since
+        // integer truncation of spacing/2 on odd values was a suspected edge case.
+        let oddSpacings = [ 3; 5; 7; 11; 13 ]
+        let evenSpacings = [ 2; 4; 6; 8; 12 ]
+        for spacing in oddSpacings @ evenSpacings do
+            let lanterns = cc0LanternTiles map spacing |> Set.ofList
+            let stalls = cc0StallTiles map spacing
+            Assert.IsTrue(lanterns.Count > 0, sprintf "spacing %d should place lanterns" spacing)
+            Assert.IsTrue(stalls.Length > 0, sprintf "spacing %d should place stalls" spacing)
+            for stall in stalls do
+                let message = sprintf "spacing %d: stall at (%d,%d) overlapped a lantern" spacing (fst stall) (snd stall)
+                Assert.IsFalse(Set.contains stall lanterns, message)
+            // The residue classes are exactly {0} and {spacing/2}, so no even/odd
+            // spacing can put a stall and a lantern on the same column.
+            for (x, _) in lanterns do
+                Assert.AreEqual<int>((0: int), x % spacing)
+            for (x, _) in stalls do
+                Assert.AreEqual<int>(spacing / 2, x % spacing)
+
+    [<TestMethod>]
+    member _.DegenerateSpacingPlacesNothing () =
+        // spacing = 1 would make spacing/2 = 0, putting stalls on the same residue
+        // class as lanterns (a real overlap). Both helpers guard spacing < 2 and
+        // return an empty set instead of overlapping.
+        for spacing in [ 0; 1; -3 ] do
+            let lanternCount: int = (cc0LanternTiles map spacing).Length
+            let stallCount: int = (cc0StallTiles map spacing).Length
+            Assert.AreEqual<int>(0, lanternCount)
+            Assert.AreEqual<int>(0, stallCount)
+
+    [<TestMethod>]
+    member _.ReedsHugTheWaterBank () =
+        let reeds = cc0ReedTiles map 4
+        Assert.IsTrue(reeds.Length > 0, "reeds should line the banks")
+        let water (tx: int) (ty: int) =
+            tx >= 0 && tx < map.Width && ty >= 0 && ty < map.Height
+            && map.Tiles.[ty * map.Width + tx] = int MapGen.GroundTile.Water
+        for (x, y) in reeds do
+            Assert.IsFalse(water x y, "reeds are placed on land")
+            Assert.IsTrue(water x (y - 1) || water x (y + 1), "reeds must touch the water bank")
+        Assert.AreEqual<string>(keyOf reeds, keyOf (cc0ReedTiles map 4))
+
+    [<TestMethod>]
+    member _.NightLightTilesIncludeRoadLanterns () =
+        // The P39 stone lanterns reuse the P29/P32 night-glow path, so every road
+        // lantern must be a light source in the night frame (cc0 mode). The
+        // backwards-compatible `nightLightTiles` keeps the old light set.
+        let cc0Lights = nightLightTilesWith true map |> Set.ofList
+        let fallbackLights = nightLightTiles map |> Set.ofList
+        for lantern in cc0LanternTiles map 12 do
+            Assert.IsTrue(Set.contains lantern cc0Lights, "road lantern must contribute night light in cc0 mode")
+            Assert.IsFalse(Set.contains lantern fallbackLights, "fallback light set must stay unchanged")
+
+    [<TestMethod>]
+    member _.SameSeedPlacesTheSameElementsAcrossCalls () =
+        // Byte-identical placement under a repeated generation of the same seed.
+        let map2 = MapGen.generateWithSize 256 192 seed
+        Assert.AreEqual<string>(keyOf3 (cc0BridgeTiles map), keyOf3 (cc0BridgeTiles map2))
+        Assert.AreEqual<(int * int) option>(cc0BoatTile map, cc0BoatTile map2)
+        Assert.AreEqual<string>(keyOf (cc0LanternTiles map 12), keyOf (cc0LanternTiles map2 12))
+        Assert.AreEqual<string>(keyOf (cc0StallTiles map 12), keyOf (cc0StallTiles map2 12))
+        Assert.AreEqual<string>(keyOf (cc0ReedTiles map 4), keyOf (cc0ReedTiles map2 4))
+        // Bridge/boat/lantern/stall/reed placement only depends on the map layout
+        // and fixed spacing (road lanterns are geometric, not seeded), so two seeds
+        // that happen to carve the same river still place the same elements. What
+        // must hold is that placement is a pure function of the map: regenerating
+        // the map from its own seed reproduces every position byte-for-byte.
+        let map3 = MapGen.generateWithSize map.Width map.Height map.Seed
+        Assert.AreEqual<string>(MapGen.serialize map, MapGen.serialize map3)