fix(vagrant): legs rotate to walk direction (user preference)

User feedback: 'Beine sollten in die richtung oszillieren, in die
gegangen wird, nicht nach norden/süden relativ zum fenster.'

Old: lower_control.rot = wedge_deg (substrate's body-relative ±30°
sub-angle), legs always oscillated near world-up axis.

New: lower_control.rot = atan(move_x, -move_y) = walk direction in
sprite-top-up convention. Legs visually rotate to align with WASD
direction → stride animation cycles along the walk axis.

Side-effect: 4-direction-anim picker collapsed to single
walk_fwd_lower (the rotation handles directional differentiation;
4 anims kept on disk for later gait-style work). Bumps puppet dep
to 0.4.1 (head south-flick fix).

init.lua

@@ -71,11 +71,18 @@ local function pick_walk_anim(num_deg)
     end
 end
 
--- HandleAnimationLower port: chooses walk anim based on signed angle between
--- body-forward and move-direction. Manages idle_lower / walk_* transitions.
+-- Lower-body controller: legs rotate to walk direction (NOT Substrate's
+-- body-relative wedge). User preference: leg stride visually aligns with
+-- movement axis. lower_control.rot = atan(move_x, -move_y) so leg sprites
+-- (which oscillate scl_y along their local Y) cycle along the walk axis.
+-- One generic walk_fwd_lower anim suffices since the rotation handles
+-- the directional change (4-direction anims kept on disk for future
+-- gait-style differentiation).
 local function update_lower_anim(moving, move_x, move_y)
     if not moving then
-        -- Idle: stop all walk anims, resume idle_lower.
+        -- Idle: stop walk anims, resume idle_lower. Preserve last
+        -- lower_control_rot_deg so legs keep their last orientation
+        -- (no snap-back to north on stop).
         if state.walk_anim_current ~= nil then
             for _, a in ipairs(WALK_ANIMS) do
                 puppet.stop(state.player, a)
@@ -91,22 +98,16 @@ local function update_lower_anim(moving, move_x, move_y)
                 ci_last_state = "idle"
             end
         end
-        state.lower_control_rot_deg = 0
         return
     end
 
-    -- Walking: read body's previous-frame world.rot for signed angle computation.
-    local _, _, body_rot = puppet.bone_world_transform(state.player, "body")
-    -- Body forward direction (sprite-top-up convention): forward = -Y at rot=0.
-    -- In world coords: fwd_x = sin(rot), fwd_y = -cos(rot).
-    local fwd_x = math.sin(body_rot)
-    local fwd_y = -math.cos(body_rot)
-    local num = signed_angle_2d(fwd_x, fwd_y, move_x, move_y)
-    local anim_id, wedge_deg = pick_walk_anim(num)
-    state.lower_control_rot_deg = wedge_deg
+    -- Walking: legs face walk direction (sprite-top convention: rot=0 = -Y).
+    state.lower_control_rot_deg = math.deg(math.atan(move_x, -move_y))
 
+    -- Single generic walk anim (4-direction-picker deferred until we have
+    -- differentiated gait styles per direction).
+    local anim_id = "walk_fwd_lower"
     if state.walk_anim_current ~= anim_id then
-        -- Swap to new walk anim.
         for _, a in ipairs(WALK_ANIMS) do
             if a ~= anim_id then puppet.stop(state.player, a) end
         end