Cut the serve down to three poses

Oliver, after playing the four-stage version on the phone: idle, then the racket
dropping on the pull, then the drive on release — "that's all, forget all the
others". At thumb speed the middle stages are never read, so they are deleted
rather than kept around: p_pull is the wind-up, p_smash is the drive, and both
come out of the photo-referenced sheet, so the whole serve is one drawing style.

The dead batches and the arm_left guard go with them. assets/_pose_ref_serve.png
is kept as the recipe: his photo sequence over our own sprites, which is what
turned a fifteen-generation prose argument into one generation.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

assets/_regen.py

@@ -91,19 +91,6 @@ def touches_edge(sheet):
         return best
     return max(run(fg[0]), run(fg[-1]), run(fg[:, 0]), run(fg[:, -1])) >= 8
 
-def arm_not_left(outs):
-    """The generator MIRRORS the later frames of a serve about half the time — the coil is a strong
-    silhouette and it draws it whichever way it likes, which puts the racket in the other hand
-    halfway through the animation. Oliver spotted it twice. Every frame after the first must reach
-    its raised arm up the LEFT-hand side, so a frame whose left half has nothing near the top (the
-    arm went right instead) is a rejected roll, not something to notice later in the file browser."""
-    for o in outs[1:]:
-        ink = np.array(Image.open(o).convert('RGBA'))[..., 3] > 128
-        h, w = ink.shape
-        left = np.nonzero(ink[:, :w // 2].any(1))[0]
-        if not len(left) or left.min() > 0.18 * h: return o
-    return None
-
 def colour_match(src, dst_name):
     """Fit the new frame onto the palette statistics of the sprite it replaces, so a redrawn body
     does not change colour halfway through a walk cycle."""
@@ -146,10 +133,6 @@ def run(name, spec, dry=False):
     print(r.stdout.strip() or r.stderr.strip())
     if r.returncode or not all(os.path.exists(o) for o in outs):
         print(f'[{name}] REJECTED: slicing failed (frames merged?) — re-run or add "cut"'); return False
-    if spec.get('arm_left'):
-        bad = arm_not_left(outs)
-        if bad:
-            print(f'[{name}] REJECTED: {bad} was drawn MIRRORED — racket in the wrong hand'); return False
     if lead: outs = outs[1:]                     # the scale reference is not installed
     before = [density(os.path.join(HERE, s + '.png')) for s in sprites]
     after = [density(o) for o in outs]