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>

HANDOFF.md

@@ -414,16 +414,11 @@ Known generator quirks, all still true:
 Oliver's notes on the art pass: the zombies are good, the runner "flickers very hard", and the
 player has three problems. The serve is now a drawn wind-up driven by the pull.
 
-- **The pull IS the wind-up.** Four new frames (`p_pull1..4`, batch `player_windup`), chosen in
-  `drawChar` off `pullFrac(G.aim.mag)`. What separates the four is HOW FAR THE RACKET HAS FALLEN, and
-  that only came out once the prompt pinned the racket head to a different BODY LANDMARK per frame —
-  above his head, beside his ear, between his shoulder blades, down at the back of his thighs.
-  Described as "further into the wind-up each time" it drew four near-identical poses twice running
-  (Oliver: *"pull3 and pull4 are now basically the same image"*), which is the generator quirk the
-  pipeline notes already warned about, in a place I did not expect it. The stages are NOT spread evenly: **frame 1 owns the whole
-  first half of the pull and the three coiled frames are packed into the top half**, Oliver's call,
-  so the part of the gesture that costs power is the part that visibly costs effort. Release fires
-  `p_smash`. Verified: 30/74/95/125 px of drag -> pull1/2/3/4.
+- **The serve is THREE poses, not an animation.** Waiting: the bounce stance. Drawing the
+  slingshot: `p_pull`, the racket dropping behind him. Release: `p_smash`, the drive. A four-stage
+  version keyed to `pullFrac` was built, wired late (frame 1 owning the first half) and played, and
+  Oliver cut it back to this — on a phone, at thumb speed, the middle stages are never read. The
+  intermediate frames are deleted, not commented out.
 - **The whole player is RIGHT-HANDED now, and that was the real bug.** `p_idle`, `p_bounce` and
   `p_toss` had been drawn holding the racket in his LEFT hand while `p_smash` and `p_swing` used his
   right, so any new frame copied whichever reference it was given and the racket changed hands
@@ -445,25 +440,28 @@ shearing a limb, cutting a prop out — a wrong frame is wrong in more ways than
 (perspective, foreshortening, where the weight sits) and none of those survive a flip. There was an
 `assets/_derive.py` doing exactly that; it is deleted. Fix the PROMPT and re-run the batch.
 
-**Three pipeline guards were added to `_regen.py`, each after a bad sheet installed silently:**
+**THE WAY TO GET A POSE RIGHT IS A PHOTO, NOT A PARAGRAPH.** Describing a serve in prose and
+re-rolling cost about fifteen generations and never landed — the racket changed hands, the four
+stages came back near-identical twice, the coil came back as a fold. Oliver's fix: give the
+generator the real thing. `scratchpad/pose_ref.png` is the recipe — his 10-frame photo sequence
+cropped to five poses in a row, with two of our own sprites underneath as the character and style
+anchor, and a prompt saying which strip means what. **One** generation returned the whole serve as
+our man in our kit, and the frames were sliced straight out of it (anchored on the standing figure
+it drew, which is what sets the scale). Note it also redraws the reference strip above the result —
+harmless, crop to the magenta band before slicing.
+
+**Two pipeline guards were added to `_regen.py`, each after a bad sheet installed silently:**
 1. **The reference's ASPECT is the answer's aspect.** One tall reference figure gave a portrait
    reference canvas and the generator answered with a 2x2 GRID, which `_fine.py` cannot cut (it
    segments columns). `ref_sheet` now widens to a landscape strip with one slot per frame asked for.
 2. **A non-magenta background is a rejected roll.** "It sometimes ignores the magenta" was written
    off as harmless because the key uses the corner colour — until it returned a GREEN sheet and keyed
    away four grey-green racket heads with it, installing four men holding a grip and nothing else.
-3. **`arm_left` rejects a MIRRORED frame.** The generator flips the later frames of a serve about
-   half the time, which puts the racket in the other hand halfway through the animation. Oliver
-   caught it twice by eye before the check existed. **It is a net, not a proof**: it asks whether
-   anything reaches the top of the LEFT half, and a mirrored frame whose racket head hangs over there
-   passes. A tighter discriminator was tried (ink mass in the top third, left vs right) and does NOT
-   separate the two — measured 0.61/0.57/0.41 on a mirrored sheet against 0.54/0.56/0.55 on a good
-   one. Every wind-up sheet still has to be looked at.
 
-Still imperfect, and worth a look on the phone: the empty tossing arm WANDERS between the four
-wind-up frames (up, out, bent, up) instead of staying thrown up at the ball. The roll that held the
-arm still put the racket back in the wrong hand, and the racket is the load-bearing half of the
-gesture, so this is the set that shipped. One more roll may fix both.
+**And `_fine.py` takes `--defringe N` (default 2).** Each de-fringe pass eats a one-pixel line, and
+a racket frame IS a one-pixel line: two passes were shredding every racket on the sheet. Detailed
+art wants 1 or 0 — there was no magenta halo left at 0 on the serve sheet, because the palette
+quantisation snaps to the sheet's own colours anyway.
 
 Also worth knowing: a batch of raised-arm poses has no honest scale to anchor on, so frame 0 is
 always a throwaway STANDING frame (`p_pull0`, deleted after installing). And a photo reference of a