feat(0.2.0): Sign as composition-Entity (Phase A.3)

Refactor spine-prototype to use lib-core.composition for the Sign:
template defines sprite_color + sprite_w + sprite_h + text + position;
create instantiates with per-instance position + text override.
Render switches from direct draw_rect to render.draw_entities{tag=
"renderable"}; interaction.register reads position from entity-properties.

Direct hardcoded `local sign = {x, y, text}` Lua-local + SIGN_R/G/B
constants entfernt. Sign demo-behavior identisch (12×12 yellow rect at
tile-center (4,4) = (144,144); E within 40px → print text).

Bumps: render dep 0.1.0 → 0.2.0; +composition v0.1.0; module 0.1.0 →
0.2.0.

Stones + Player bleiben Lua-locals (A.5/A.6 territory).

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

init.lua

@@ -5,7 +5,8 @@ local input       = require("lib-core.input")
 local player      = require("lib-core.player_control")
 local interaction = require("lib-core.interaction")
 local selection   = require("lib-core.selection")
-local command    = require("lib-core.command")
+local command     = require("lib-core.command")
+local composition = require("lib-core.composition")
 
 local demo_map = maps.load("maps/demo.map.json")
 maps.set_current(demo_map)
@@ -63,10 +64,28 @@ player.bind_movement("move_left", "move_right", "move_up", "move_down")
 
 local PLAYER_R, PLAYER_G, PLAYER_B = 200, 60, 80
 
--- Sign as module-local (actor deferred — see actor-deferral spec)
--- Tile (4,4) center: 4*32+16 = 144 px in walkable grass-area
-local sign = { x = 144, y = 144, text = "Hier steht: Willkommen im Spine." }
-local SIGN_R, SIGN_G, SIGN_B = 220, 200, 60
+-- Sign-Template (Phase A.1 — composition + Inactive-Entity-Pattern).
+-- Position-Property is the visual CENTER per render.draw_entities convention.
+composition.define_template{
+    id = "sign",
+    properties = {
+        sprite_color = engine.render.rgb(220, 200, 60),
+        sprite_w     = 12,
+        sprite_h     = 12,
+        text         = "default sign text",
+        position     = {x = 0, y = 0},
+    },
+    tags = {"renderable"},
+}
+
+-- Instantiate the demo sign at tile (4,4)-center = 144 px in grass-area.
+local sign = composition.create{
+    template = "sign",
+    properties = {
+        position = {x = 144, y = 144},
+        text     = "Hier steht: Willkommen im Spine.",
+    },
+}
 
 -- P.3.6/P.3.7: 6 stones as selectables + movable units (3 speed classes).
 local stones = {
@@ -102,9 +121,16 @@ function init(ctx)
     engine.print(string.format("player: pos=(%d,%d) size=%dx%d speed=%d",
         p.x, p.y, s.w, s.h, player.speed()))
 
-    interaction.register(sign.x, sign.y, 40, "interact", function(info)
-        engine.print(sign.text)
-    end)
+    -- Position + text are read once at registration; the sign is stationary
+    -- in v0.1 so a snapshot is correct. If it ever moves, the interaction-
+    -- API would need closure-form anchor (currently raw-number-only).
+    interaction.register(
+        sign:get_property("position.x"),
+        sign:get_property("position.y"),
+        40, "interact",
+        function(info)
+            engine.print(sign:get_property("text"))
+        end)
     engine.print(string.format("interaction: %d trigger(s) registered",
         interaction.trigger_count()))
     -- P.3.6/P.3.7: Register each stone as selectable AND movable.
@@ -128,9 +154,8 @@ function render(ctx)
     engine.render.clear_color(engine.render.rgb(20, 20, 30))
     camera.begin()
         maps.draw_map_pre_entities()
-        -- draw sign on top of map
-        engine.render.draw_rect(sign.x - 6, sign.y - 6, 12, 12,
-            engine.render.rgb(SIGN_R, SIGN_G, SIGN_B))
+        -- draw all renderable entities (Phase A.2: tag-based render)
+        r_lib.draw_entities{ tag = "renderable" }
         -- P.3.6: draw stones
         for _, s in ipairs(stones) do
             engine.render.draw_rect(s.x, s.y, s.w, s.h,