feat: v0.13.0 Workbench multi-panel via panel v0.2.0

D.2-revisit closes the Workbench Gate-2 walkthrough: right-click
on Workbench now opens workbench_crafting (left-half layout-slot)
+ workbench_inv (right-half) simultaneously, replacing the v0.12.0
auto-switch workaround. Both panels visible at the same time.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

init.lua

@@ -1,4 +1,4 @@
--- sporel-module-vagrant-skeleton v0.12.0
+-- sporel-module-vagrant-skeleton v0.13.0
 -- Sprite-mode test-chamber: 13-bone humanoid puppet + sprite-tilemap +
 -- hardcoded furniture. Subterrain-style puppet control model:
 -- multi-look-target (aim/soft), slerp body rotation, hip-static legs,
@@ -57,9 +57,12 @@
 -- in the workbench. Take-action in workbench-inv moves an item back
 -- to the backpack. C-key Backpack-Crafting remains via the bw-compat
 -- shim in crafting v0.2.0 (Form-1 bare entity-handle stays valid).
--- Panel-lib v0.1 is single-active so opening both panels lets
--- workbench_inv win; user can close it (X) to reveal workbench_crafting
--- below — Gate-2 walkthrough documents the flow.
+--
+-- v0.13.0: lib-core.panel bumped to 0.2.0 (multi-active + layout-slots).
+-- Workbench-Crafting registers with layout="left-half", Workbench-
+-- Inventory with layout="right-half"; right-click opens both panels
+-- simultaneously side-by-side. Replaces the v0.12.0 single-active
+-- caveat where workbench_inv covered workbench_crafting.
 
 local input       = require("lib-core.input")
 local camera      = require("lib-core.camera")
@@ -297,16 +300,13 @@ end
 -- Workbench-Inventory panels.
 --
 -- lib-core.interaction v0.1.0 is XY-based (not entity-bound); the trigger
--- snapshots the position at registration time. Workbench is static in v0.12
--- so a single registration suffices. Action-name "use" is bound to
--- mouse_right in M.init's input.bind block.
+-- snapshots the position at registration time. Workbench is static so a
+-- single registration suffices. Action-name "use" is bound to mouse_right
+-- in M.init's input.bind block.
 --
--- Note on dual-panel-open: lib-core.panel v0.1.1 enforces a single active
--- widget. Calling panel.open twice means the second call wins
--- (workbench_inv shows on top; workbench_crafting is hidden until the
--- player closes the inv panel via X). This matches the spec §4.4 note that
--- "v0.2 default ist whatever panel-lib default" — proper side-by-side
--- layout is a panel-lib v0.2 task, out of scope for D.2.
+-- panel v0.2.0 supports multi-active panels with layout-slots; the two
+-- panels (workbench_crafting=left-half, workbench_inv=right-half) are
+-- visible simultaneously side-by-side after both panel.open calls.
 local function register_interaction_use(entity)
     local x = entity:get_property("position.x")
     local y = entity:get_property("position.y")
@@ -882,7 +882,8 @@ function M.init(ctx)
             ctx_inner.close_menu()
         end)
 
-    panel.register("workbench_crafting", state.workbench_crafting_widget)
+    panel.register("workbench_crafting", state.workbench_crafting_widget,
+        {layout = "left-half"})
     -- KEIN bind_default_trigger: trigger is the workbench right-click via
     -- register_interaction_use(state.workbench) below.
 
@@ -934,7 +935,8 @@ function M.init(ctx)
             c.close_menu()
         end)
 
-    panel.register("workbench_inv", state.workbench_inv_widget)
+    panel.register("workbench_inv", state.workbench_inv_widget,
+        {layout = "right-half"})
 
     -- Right-click trigger registered AFTER both workbench widgets are
     -- panel.register'd; the callback panel.open()s them by id, so they