Add formal enemies, remaining formal partners and synthesized UI SFX

- UI SFX v3: procedurally synthesized one-shots (Tools/synth_ui_sfx.py) wired to
  buttons, rewards, errors and red dots via UiSfx, gated by the SFX setting.
- Five formal enemies (Hornlet, Dashlet, Shellhorn, HornCaptain, GreatHorn):
  Hunyuan 50k -> 2000-tri XPbr, DGXA TokenRig, Idle/Walk/Attack, nested per type
  in PrototypeArena; PrototypeBattle.Enemy gains presentation-only Moving/Strikes.
- Formal partners for all ten pets in the arena and portraits, including new
  VineSprite, ThunderLeopard and TideWhale.
- Pipeline fixes: reject local TokenRig fallback, drop loose mesh islands,
  configurable Unity run_script timeout, companion static stage.
- Also includes concurrent work from another tool in this working tree
  (FlameLion, enemy combat FX, challenge mode, home explorer, server updates).
- Resources registered in Doc/ResDesc_*.md; verified on isolated :18081.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Doc/Design/Character/BubbleTurtle/design_prompt.txt

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+Use case: stylized-concept.
+Asset type: a single production character concept image for image-to-3D, BubbleTurtle (泡泡龟), T1 water-element guardian companion for the same polished cute fantasy mobile game.
+Input images: image 1 proto_pet_4 is ONLY the identity reference: turquoise/aqua domed turtle shell, aqua rounded head, four short cream feet, low four-legged turtle silhouette. Image 2 FireCat is ONLY the established polished 3D art style, collectible proportions and high-quality expressive eyes reference. Create a turtle, never a cat and never a standing biped.
+Primary request: an appealing little fantasy land turtle, sturdy rounded squat quadruped with a thick smooth domed turquoise shell on its back, a few broad simple hexagonal scutes in slightly darker aqua, broad solid cream shell rim, large friendly aqua-blue head with a short visible neck projecting clearly out in front of the shell, expressive glossy deep-blue eyes with small readable whites, tiny happy mouth appropriate for blowing a bubble spell. Cream pale-yellow chin and underside. FOUR separate short stout legs, cream rounded feet with only two or three broad subtle toe divisions; all four legs support a normal horizontal quadruped turtle body. A tiny compact aqua tail, subtle pale water-drop-shaped mark integrated into the central shell scute, no detached ornaments. No clothing, fur or cat features. Friendly steadfast guardian personality, basic T1 form.
+Materials/style: polished stylized 3D studio character render matching FireCat's quality, smooth gently textured reptile skin and softly satin shell with clear solid volumes; strong clean silhouette, no realistic harsh reptile scales, no plastic toy seams, no see-through shell.
+Composition: ONE creature, whole body centered in an informative front three-quarter view, camera slightly above eye level so the shell dome and the friendly face are both visible; four feet clearly separated and as readable as possible, spaced naturally with visible gaps between legs and shell so joints can be rigged, not fused flippers. Head faces toward the viewer and slightly to one side without twisting the neck, body naturally horizontal and all feet grounded. Full shell, head, feet and small tail in frame, generous pure-white margins. Landscape 3:2 framing appropriate for a broad low turtle.
+Lighting/backdrop: soft neutral studio lighting, PURE SOLID WHITE RGB255 background including all four corners, minimal soft contact shadow immediately under feet.
+Constraints: suitable for a clean 2000-triangle game model, a single rigid thick shell, broad scutes rather than many tiny pieces, thick connected forms, no floating bubbles, water jets, particles, transparent effects, puddle, pedestal, props, environment, text, labels, multiple views, watermark, weapons or armor. Do not turn the turtle into a humanoid, a sea turtle with flippers, a spiky tortoise, or a shell-less animal.
+
+Mode: built-in image_gen, new character concept using reference images.
+Identity reference: AIClient/Assets/Bundles/UI/Texture/Prototype/proto_pet_4.png
+Style reference: Doc/Design/Character/FireCat/firecat.png
+Output: Doc/Design/Character/BubbleTurtle/bubbleturtle.png (1536x1024).