feat(render): #85 engine sprite-render system + deprecate bare draw_sprite

The engine already auto-ticks SpriteAnim/Motion; it now auto-DRAWS too.
Declare a Sprite component (id/offx/offy/scale/flip/tint/hidden, shipped from
ludic.core) on an entity with a Position and esys_sprite draws it each Render
frame — no hand-written Render handler, no hand animation (adds the SpriteAnim
frame when present). Registered on the engine-system registry (Render) and
spliced only when the game declares Sprite, so a game that never declares it
compiles byte-identically; opt out by omitting Sprite or `disable system
esys_sprite`.

Deprecates the bare draw_sprite/draw_sprite_scaled globals in favour of
Screen.sprite/Screen.sprite_scaled: a direct bare call emits a one-time
compile-time deprecation note (the bare form still lowers, since Screen.sprite
uses it); migrates the chronorift demo to the namespaced calls (golden render
byte-identical).

Example sprite_render (pixel-readback: engine draws the sprite, respects
hidden). Full suite 109/0, goldens byte-identical, fixpoint holds.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

examples/games/chronorift/draw.ludic

@@ -24,19 +24,19 @@ handler Draw phase Render {
           ',', 'S', 'B' => base = SPR_FLOOR
           '=' => base = SPR_WALL
         }
-        draw_sprite(base, sx, sy)
-        if c == 'T' { draw_sprite(SPR_TREE, sx, sy) }
-        if c == '#' { draw_sprite(SPR_TREE, sx, sy) }
-        if c == 'H' { draw_sprite(SPR_HOUSE, sx, sy) }
-        if c == 'D' { draw_sprite(SPR_DOOR, sx, sy) }
-        if c == 'S' { draw_sprite(SPR_DOOR, sx, sy) }
+        Screen.sprite(base, sx, sy)
+        if c == 'T' { Screen.sprite(SPR_TREE, sx, sy) }
+        if c == '#' { Screen.sprite(SPR_TREE, sx, sy) }
+        if c == 'H' { Screen.sprite(SPR_HOUSE, sx, sy) }
+        if c == 'D' { Screen.sprite(SPR_DOOR, sx, sy) }
+        if c == 'S' { Screen.sprite(SPR_DOOR, sx, sy) }
         if c == 'B' {
-          if boss_down == 0 { draw_sprite(SPR_BOSS, sx, sy) }
+          if boss_down == 0 { Screen.sprite(SPR_BOSS, sx, sy) }
         }
       }
     }
     for (p, a) in query [Pos, Actor] {
-      draw_sprite(a.kind, p.x * 16 - cx, p.y * 16 - cy)
+      Screen.sprite(a.kind, p.x * 16 - cx, p.y * 16 - cy)
     }
     for (h, pp) in query [Stats, Party] {
       if pp.slot == 0 {
@@ -59,7 +59,7 @@ handler Draw phase Render {
     for (e, a) in query [Stats, Actor, {Enemy}] {
       var bs = 5
       if enemy_type == 2 { bs = 7 }
-      draw_sprite_scaled(a.kind, 160 - bs * 8, 44, bs)
+      Screen.sprite_scaled(a.kind, 160 - bs * 8, 44, bs)
       Screen.draw_text(100, 20, enemy_name(enemy_type), 0xffffff, 1)
       Screen.fill_rectangle(100, 30, 120, 8, 0x401018)
       Screen.fill_rectangle(100, 30, e.hp * 120 / e.maxhp, 8, 0xe04040)
@@ -75,7 +75,7 @@ handler Draw phase Render {
       var spr = 5
       if pt.slot == 1 { spr = 9 }
       if pt.slot == act { Screen.draw_rectangle(hx - 2, 180, 88, 44, 0xffff00) }
-      draw_sprite_scaled(spr, hx, 184, 2)
+      Screen.sprite_scaled(spr, hx, 184, 2)
       if pt.slot == 0 { Screen.draw_text(hx + 36, 182, "KNIGHT", 0xffe08a, 1) }
       if pt.slot == 1 { Screen.draw_text(hx + 36, 182, "MAGE", 0xc9a0ff, 1) }
       Screen.draw_text(hx + 36, 195, "HP", 0x88ff88, 1)

examples/library/sprite_render.ludic

@@ -0,0 +1,32 @@
+# sprite_render.ludic — the engine-owned sprite-render system (#85). Declare a
+# Sprite component (from ludic.core) on an entity with a Position and the engine
+# draws it each Render frame — no hand-written Render handler querying positions
+# and calling draw_sprite per entity. A `hidden` sprite is skipped. Verified by
+# pixel readback after one frame.
+#
+# Driven headless by one stdin key ('q' quits after the frame renders).
+#   printf 'q' | LUDIC_MODULES=packages bin/ludic examples/library/sprite_render.ludic  ->  1 0
+program SpriteRender {
+  import "ludic.core/components.ludic"
+
+  var HERO: int = 0
+
+  @OnStart handler Boot {
+    HERO = png_load("assets/kenney/tiny-dungeon/Tiles/tile_0096.png")
+    spawn Shown  { Position { x: 40, y: 40 },  Sprite { id: HERO } }
+    spawn Hidden { Position { x: 100, y: 40 }, Sprite { id: HERO, hidden: 1 } }
+  }
+
+  # An empty Render handler: the engine sprite system draws the Sprite entities.
+  handler Draw phase Render { }
+
+  @OnQuit handler Report {
+    var drew = 0
+    for yy in 40 .. 56 { for xx in 40 .. 56 { if Screen.pixel(xx, yy) != 0 { drew = 1 } } }
+    print(drew)                          # 1 — the engine drew the shown sprite
+
+    var hid = 0
+    for yy in 40 .. 56 { for xx in 100 .. 116 { if Screen.pixel(xx, yy) != 0 { hid = 1 } } }
+    print(hid)                           # 0 — the hidden sprite was skipped
+  }
+}