feat(vagrant): v0.3.0 — substrate-port rig + animations + locomotion

- humanoid.rig.json rewrite: legs->root, rest.rot+rest.scl on all bones,
  Y-mirror via scl=-1 on leg_l/r/foot_l/r, locomotion-block with
  procedural footplant config
- walk.anim.json: substrate walk_fwd_lower port; track=lower; pos+scl
  channels on legs+feet
- walk_upper.anim.json (NEW): substrate walk_upper port; arm-swing
- idle.anim.json: substrate idle_upper port; pos+rot on shoulders+arms
- init.lua: walk_upper parallel-play wiring
- manifest bump v0.2->v0.3; puppet dep ^0.3.0

animations/idle.anim.json

@@ -1,11 +1,38 @@
 {
-    "id": "idle",
-    "track": "upper",
-    "duration": 2.0,
-    "loop": true,
-    "keyframes": [
-        { "t": 0.0, "body": {"angle":  0}, "head": {"angle":  0} },
-        { "t": 1.0, "body": {"angle":  2}, "head": {"angle": -1} },
-        { "t": 2.0, "body": {"angle":  0}, "head": {"angle":  0} }
-    ]
+  "id": "idle",
+  "track": "upper",
+  "duration": 2.0,
+  "loop": true,
+  "keyframes": [
+    {
+      "t": 0,
+      "body": { "rot": 0 },
+      "shoulders": { "pos": [0, 0], "rot": 0 },
+      "upper_arm_l": { "rot": -15 },
+      "lower_arm_l": { "rot": 10 },
+      "upper_arm_r": { "rot": 15 },
+      "lower_arm_r": { "rot": -10 },
+      "head": { "rot": 0 }
+    },
+    {
+      "t": 1,
+      "body": { "rot": 0 },
+      "shoulders": { "pos": [0, -0.5], "rot": 0 },
+      "upper_arm_l": { "rot": -13 },
+      "lower_arm_l": { "rot": 8 },
+      "upper_arm_r": { "rot": 13 },
+      "lower_arm_r": { "rot": -8 },
+      "head": { "rot": 0 }
+    },
+    {
+      "t": 2,
+      "body": { "rot": 0 },
+      "shoulders": { "pos": [0, 0], "rot": 0 },
+      "upper_arm_l": { "rot": -15 },
+      "lower_arm_l": { "rot": 10 },
+      "upper_arm_r": { "rot": 15 },
+      "lower_arm_r": { "rot": -10 },
+      "head": { "rot": 0 }
+    }
+  ]
 }