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>

Config/Art/EnemyCharacters/Shellhorn.json

@@ -0,0 +1,70 @@
+{
+  "schemaVersion": 1,
+  "id": "Shellhorn",
+  "kind": "Enemy",
+  "usage": "enemy_visual",
+  "profile": "biped_short",
+  "boneMappingReady": true,
+  "height": 0.5,
+  "maxTriangles": 2000,
+  "assetRoot": "Assets/Bundles/Characters/Enemy/Shellhorn",
+  "staticPrefab": "Assets/Bundles/Characters/Enemy/Shellhorn/Shellhorn.prefab",
+  "approvedMesh": "AIClient/Assets/Bundles/Characters/Enemy/Shellhorn/Shellhorn.fbx",
+  "rigSource": "Tools/output/enemy_dgx/Shellhorn/high_rig/rigged.glb",
+  "lowUp": "Y",
+  "skinOverrides": [],
+  "outputDir": "Tools/output/enemy_characters/Shellhorn",
+  "enemyPrefab": "Assets/Bundles/Characters/Enemy/Shellhorn/Shellhorn_Enemy.prefab",
+  "reviewScene": "Assets/Bundles/Scenes/Review/Enemy_Shellhorn_Review.unity",
+  "reviewOriginX": 180,
+  "rootBone": "bone_0",
+  "chestBone": "bone_3",
+  "faceRight": "bone_22",
+  "faceLeft": "bone_26",
+  "rightFoot": "bone_22",
+  "leftFoot": "bone_26",
+  "rightFootTip": "bone_23",
+  "leftFootTip": "bone_27",
+  "rightArm": "bone_6",
+  "leftArm": "bone_13",
+  "walkStride": 0.055,
+  "walkLift": 0.016,
+  "walkSeconds": 1.2,
+  "walkBindCalibration": true,
+  "walkSourceWeight": 0.25,
+  "idleSeconds": 1.8,
+  "idleBreath": 0.003,
+  "idleSourceWeight": 0.06,
+  "attackStyle": "body_slam",
+  "attackSeconds": 1.0,
+  "attackSourceWeight": 0.1,
+  "attackWindup": 0.25,
+  "attackImpact": 0.45,
+  "attackRecover": 0.88,
+  "attackLeanDegrees": 14,
+  "attackArmDegrees": 25,
+  "attackLunge": 0.025,
+  "maxRootTilt": 25,
+  "groundTolerance": 0.003,
+  "anatomyNotes": "Inspected this Shellhorn DGXA TokenRig original: 28 bones (same topology as HornCaptain, own rig). Root0, spine1..3 (chest3), neck4/head5; x-positive arm6..8 with hand chain9..12, x-negative arm13..15 with chain16..19 from chest3; x-positive leg20/21/22 ankle/23 toe, x-negative 24/25/26/27 from root0. Back stone shell, brow plate and horn have no independent bones; check the shell stays rigid on the chest/spine at the attack peak.",
+  "motions": [
+    {
+      "name": "Idle",
+      "sourceDir": "Tools/output/enemy_characters/Shellhorn/motions/Idle",
+      "prompt": "a stocky small bipedal imp with a heavy stone shell on its back stands upright and idles with slow gentle breathing",
+      "duration": 2.0
+    },
+    {
+      "name": "Walk",
+      "sourceDir": "Tools/output/enemy_characters/Shellhorn/motions/Walk",
+      "prompt": "a stocky small bipedal imp with a heavy stone shell walks forward upright with slow alternating short steps",
+      "duration": 2.0
+    },
+    {
+      "name": "Attack",
+      "sourceDir": "Tools/output/enemy_characters/Shellhorn/motions/Attack",
+      "prompt": "a small bipedal character performs one forward body slam attack and recovers to standing",
+      "duration": 2.0
+    }
+  ]
+}