zen: rebuild UB locomotion — real 3D steering + motionRoot/visualRig split (Codex)

Not a tuning pass — a locomotion rebuild per Codex's review. Replaces the X-axis shuttle +
scripted 180° U-turn with a proper 3D steering controller (behavior.js): UB seeks wandering
waypoints through the whole tank (XYZ incl. near/far depth passes), eases speed via limited
accel, steers with a rate-limited quaternion toward its velocity, banks into curves, and
softly veers away from walls BEFORE reaching them — no scripted turns.

Architecture: motionRoot (Group) owns world position + heading + bank; the visual rig plays
in-place body clips inside it, so navigation never fights the skeleton and the controller is
the sole heading authority (clips carry no root motion — verified). Fuller clip set exported
(idle/cruise/fast/turn{L,R}{in,loop,out}/eat*, build-clips.mjs). Authored clips play at their
own timing; only cruise cadence scales with speed. Debug panel: cruise speed + roam W/H/DEPTH
+ liveliness, a live readout (mode/clip/speed/turn/pos), and the raw-clip preview.

Next (Codex step 3): needs-driven personality — forage/zoomies/surface/inspect — on this base.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tools/glb-split/build-clips.mjs

@@ -14,13 +14,15 @@ const root = doc.getRoot();
 const buffer = root.listBuffers()[0];
 const meta = JSON.parse(fs.readFileSync(new URL('./angelfish-clips.json', import.meta.url))).clips;
 
-// output-clip-name -> source clip in the pack
+// output-clip-name -> source clip in the pack. Full turn SEQUENCES (in→loop→out) so the
+// controller can play a real turn; swim intensities for cadence/zoomies; eats for forage.
 const MAP = {
-  idle:   'Idle',
-  cruise: 'Swim1_norm',
-  burst:  'Swim2_Fast',
-  turnL:  'Turn_L_loop',
-  turnR:  'Turn_R_loop',
+  idle:     'Idle',
+  cruise:   'Swim1_norm',
+  fast:     'Swim2_Fast',
+  turnLin:  'Turn_L_in',  turnLloop: 'Turn_L_loop',  turnLout: 'Turn_L_out',
+  turnRin:  'Turn_R_in',  turnRloop: 'Turn_R_loop',  turnRout: 'Turn_R_out',
+  eatswim:  'Eat_Swim',   eatground: 'Eat_Ground',
 };
 
 const src = root.listAnimations()[0];