feat(art): 角色六帧动画与水面/炊烟三相循环

- 角色图集每个 (变体,方向) 由 2 帧扩到 6 帧（4 走路 + 2 待机呼吸），
  cellIndex=(variant*4+direction)*6+frame，图集 3840x48
- 世界图集扩到 25 格 800x32：水面第 3 相 WaterSpriteC(slot 21)、
  炊烟三帧 SmokeSpriteA/B/C(slot 22-24)
- 帧选择为纯函数：walk=(tick/4)%4、idle=(tick/24)%2、
  water=(tick/32)%3、smoke=(tick/40)%3
- 重生成 jiangnan/cc0 图集（脚本可复现，逐字节一致）

1 files changed, 16 insertions, 8 deletions

diff --git a/scripts/make-cc0-art.py b/scripts/make-cc0-art.py
index 897ec4f..f5c97ee 100644
--- a/scripts/make-cc0-art.py
+++ b/scripts/make-cc0-art.py
@@ -5,7 +5,7 @@ Reads the two provenanced CC0 packs in third_party/ (Kenney Tiny Farm tiles,
 Puny Characters) and emits Deterministic CC0 Atlases for the prototype:
 
   src/LivingVillage.Desktop/Assets/cc0-tiles.png      128x32 (4 ground tiles, 32px each)
-  src/LivingVillage.Desktop/Assets/cc0-characters.png 2560x48 (5 variants x 4 directions x 4 frames, 32x48 cells)
+  src/LivingVillage.Desktop/Assets/cc0-characters.png 3840x48 (5 variants x 4 directions x 6 frames, 32x48 cells)
 
 Mapping strategy (16 -> 32): integer 2x nearest-neighbour upscale of every source
 sprite; ground tiles fill the 32x32 cell exactly; Puny sprites keep their
@@ -115,14 +115,18 @@ def build_cc0_tile_atlas():
 
 
 def build_cc0_character_atlas():
-    """5 variants x 4 directions x 4 frames of 32x48 cells from Puny characters.
+    """5 variants x 4 directions x 6 frames of 32x48 cells from Puny characters.
 
     Layout: each 32x48 CELL = source 16x24 content band scaled 2x (32x48), anchored
     bottom (feet on the ground line). Directions: the pack provides south-facing
     art only; south/north use the same band (pack limitation recorded in the
     commit), west/east are mirrored copies so walkers always read toward the player.
+
+    Frames 0-3 are the walk cycle (source poses 0-3). Frames 4-5 are the idle
+    breath cycle: the neutral pose (source pose 0) relaxed, then raised 1px for
+    the inhale. The pack has no dedicated idle art, so this reuses pose 0.
     """
-    c = Canvas(2560, 48)
+    c = Canvas(3840, 48)
 
     variant_files = [
         "Soldier-Blue.png",
@@ -143,12 +147,16 @@ def build_cc0_character_atlas():
     cell_w = 32
     for vi, pose_cells in enumerate(variants):
         for di in range(4):
-            for frame in range(4):
-                sprite = pose_cells[frame].resize((32, 48), Image.NEAREST)
+            # Walk frames reuse poses 0-3; idle frames 4-5 reuse the neutral pose 0,
+            # with frame 5 raised 1px so the pair reads as a breath.
+            frame_poses = [pose_cells[0], pose_cells[1], pose_cells[2], pose_cells[3], pose_cells[0], pose_cells[0]]
+            frame_offsets = [0, 0, 0, 0, 0, -1]
+            for frame in range(6):
+                sprite = frame_poses[frame].resize((32, 48), Image.NEAREST)
                 if di in (1, 3):
                     sprite = sprite.transpose(Image.FLIP_LEFT_RIGHT)
-                ox = cell_w * ((vi * 4 + di) * 4 + frame)
-                c.blit(sprite, ox, 0, scale=1)
+                ox = cell_w * ((vi * 4 + di) * 6 + frame)
+                c.blit(sprite, ox, frame_offsets[frame], scale=1)
     return c
 
 
@@ -158,7 +166,7 @@ def main():
     ASSETS.mkdir(parents=True, exist_ok=True)
     targets = [
         ("cc0-tiles.png", build_cc0_tile_atlas(), 128, 32),
-        ("cc0-characters.png", build_cc0_character_atlas(), 2560, 48),
+        ("cc0-characters.png", build_cc0_character_atlas(), 3840, 48),
     ]
     for name, canvas, w, h in targets:
         path = ASSETS / name