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/walk.anim.json

@@ -1,14 +1,28 @@
 {
-    "id": "walk",
-    "track": "lower",
-    "duration": 0.6,
-    "loop": true,
-    "keyframes": [
-        { "t": 0.0, "leg_l":  {"angle": -20}, "leg_r":  {"angle":  20},
-                    "foot_l": {"angle":  10}, "foot_r": {"angle": -10} },
-        { "t": 0.3, "leg_l":  {"angle":  20}, "leg_r":  {"angle": -20},
-                    "foot_l": {"angle": -10}, "foot_r": {"angle":  10} },
-        { "t": 0.6, "leg_l":  {"angle": -20}, "leg_r":  {"angle":  20},
-                    "foot_l": {"angle":  10}, "foot_r": {"angle": -10} }
-    ]
+  "id": "walk",
+  "track": "lower",
+  "duration": 0.8,
+  "loop": true,
+  "keyframes": [
+    { "t": 0.0,
+      "leg_l":  {"scl": [-1,  0]},  "leg_r":  {"scl": [ 1,  0]},
+      "foot_l": {"pos": [0, 0]},    "foot_r": {"pos": [0, 0]}
+    },
+    { "t": 0.2,
+      "leg_l":  {"scl": [-1, -1]},  "leg_r":  {"scl": [ 1,  1]},
+      "foot_l": {"pos": [-0.044,  25.47]},  "foot_r": {"pos": [0.249,  25.85]}
+    },
+    { "t": 0.4,
+      "leg_l":  {"scl": [-1,  0]},  "leg_r":  {"scl": [ 1,  0]},
+      "foot_l": {"pos": [0, 0]},    "foot_r": {"pos": [0, 0]}
+    },
+    { "t": 0.6,
+      "leg_l":  {"scl": [-1,  1]},  "leg_r":  {"scl": [ 1, -1]},
+      "foot_l": {"pos": [ 0.044, -25.47]},  "foot_r": {"pos": [-0.249, -25.85]}
+    },
+    { "t": 0.8,
+      "leg_l":  {"scl": [-1,  0]},  "leg_r":  {"scl": [ 1,  0]},
+      "foot_l": {"pos": [0, 0]},    "foot_r": {"pos": [0, 0]}
+    }
+  ]
 }