feat(engine): #90 atlas-aware Sprite component, #91 become from listeners, 0.3.x ergonomics batch

Closes the two open issues and lands the pending unreleased batch:

- #90: `Sprite { atlas: 1 }` routes esys_sprite through atlas_draw_ex
  (scale/flip/tint), so cell / cell_span / strip ids of any size draw
  through the engine sprite-render system. examples/library/sprite_atlas
  is the pixel-readback regression.
- #91: `become` from an @On(Event) listener / global handler / plain
  function no longer segfaults the compiler; it emits @L_scene_leave()
  (a dispatch on the live scene id) so the leaving scene's on-exit runs.
  UI_* handles are readable from any code (widget table built on first
  use). examples/library/scene_menus covers it.
- fix: a windowed `ludicc -o` build that reaches the audio runtime only
  through the atlas/Assets preload import now links audio.ll +
  AVFoundation (the audio backend link was gated on a game-level
  Audio.* call, so any windowed game declaring Sprite failed to link).
- the hand-written "Unreleased" CHANGELOG section is converted to
  changesets under changes/ so `x release` generates it.
- plus the batch: engine-driven retained UI + UiClicked event, Overlay
  phase, TileSkin tilemap-render system, Key.* constants, Font/Ui/File
  namespaces, Sprite.strip, prefabs, managers, countdown fields,
  enum-typed machines, layer @Queries, ludic.prefs / ludic.dungeon
  packages, Ai.seek pathing, Solids.solid2, cursor confine (mode 3)
  fix, shooter centre-aim fix, reserved-word function diagnostic.

Verified: x test (124/124), x test-tools, check-impl, check-vocabulary,
check-docs, docs-gen + docs-check, bootstrap-cfree (seed is a fixpoint).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tools/x/selfhost.ludic

@@ -47,6 +47,7 @@ function selfhost_frags() -> []pointer {
   push(f, "selfhost/backend/stdlib/emit_datetime.ludic")
   push(f, "selfhost/backend/stdlib/emit_colorfn.ludic")
   push(f, "selfhost/backend/stdlib/emit_color.ludic")
+  push(f, "selfhost/backend/stdlib/emit_key.ludic")
   push(f, "selfhost/backend/emit_new.ludic")
   push(f, "selfhost/backend/emit_expr.ludic")
   push(f, "selfhost/backend/emit_call.ludic")

tools/x/test.ludic

@@ -267,12 +267,18 @@ function cmd_test() -> int {
   # builtin gameplay controllers, consumed as in-repo packages (issues #57-#61)
   controller_case("library/core_components", "", "110 30 184 1", "core_components.ludic (ludic.core #77: canonical Position/Body/Collider imported from a package, driving esys_move, composed with a game Health component)")
   controller_case("library/sprite_render", "q", "1 0", "sprite_render.ludic (ludic.core #85: engine sprite-render system auto-draws a Sprite entity from its Position; respects hidden)")
+  controller_case("library/sprite_atlas", "q", "32 1 1 1 0", "sprite_atlas.ludic (#90 Sprite { atlas: 1 } routes esys_sprite through atlas_draw_ex: a 16x32 cell_span draws both cells, tint applies, atlas: 0 stays a table id)")
   controller_case("library/world_bounds", "", "184 -16 184 1 0", "world_bounds.ludic (ludic.core #84: engine world-bounds system — clamp/wrap/bounce/kill keep a Body in the play area)")
   controller_case("library/gameplay_foundation", "", "2 0 1 5 24 0 2 1 15 85 7 1 1", "gameplay_foundation.ludic (ludic.gameplay #57: Cooldown timer + Stats/modifier stack + Faction table + Combat cancel/mutable pipeline)")
   controller_case("games/platformer_demo", "", "1 1 1 1 1 1 1 1", "platformer_demo.ludic (ludic.platformer #58: gravity/land, jump apex, coyote, veto-gated double jump, wall collision + disable-system lever)")
   controller_case("games/platformer_scaffolding", "", "1 1 1 1 1 1", "platformer_scaffolding.ludic (ludic.platformer #58 layers 4-5: moving-platform rider carry, pickup->score, spring, hazard+Life i-frames)")
   controller_case("games/shooter_demo", "", "1 1 1 1 1 1 1 1 1 1 1", "shooter_demo.ludic (ludic.shooter #60: decoupled move/aim, weapon registry, projectile faction-hit, spread/ring, homing, wave spawner)")
   controller_case("games/npcai_demo", "", "1 1 1 1 1 1 1 1", "npcai_demo.ludic (ludic.npcai #61: perception/spot, FSM chase+attack driving the shooter weapon, utility flee, companion follower)")
+  controller_case("library/prefabs", "", "230159 30 0 7 44 -1 2", "prefabs.ludic (prefab chains, spawn as an expression, Prefab.spawn / spawn_at by name, self() in @OnSpawn)")
+  controller_case("library/component_access", "xxxxxxxx", "9 15 10 33 1 0 0 1 0 1 101 100 102 1 2 1 0", "component_access.ludic (Prop.of/has/count/despawn_all, countdown fields, enum-typed machine)")
+  controller_case("library/scene_menus", "xxxxxxxxxxxx", "100 200 201 1 202 300 6 7 8", "scene_menus.ludic (become from a listener, layer @Queries, scene shows / lasts, goto: buttons)")
+  controller_case("library/managers", "xxxxxxxxxxxx", "35046 46 251 53 900 -1 20 324 0 10 102", "managers.ludic (Map cell API, Sprite move/face/flash/blink, IVec2 geometry, List.sample, Input.move_i, Fx, audio bank, Camera.shake_for)")
+  controller_case("library/combat_kit", "xxxxxxxxxxxx", "6846 153196 31 107110 6000 5002 1 80 97 11 10 700 110", "combat_kit.ludic (Dash, Melee + MeleeHit, build stats in Combat.damage + Crit, Stats.add, Dungeon arena / exits / entry points, Prefs.max)")
   controller_case("games/rpg_demo", "", "1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1", "rpg_demo.ludic (ludic.rpg #59 all 7 modules: grid move+veto+interact, inventory+equip, crafting, quests, dialog graph, sokoban+signal gate, poison status)")
   spec_case("library/testing", "== 6 passed, 0 failed ==")
   spec_case("library/coverage", "== 3 passed, 0 failed ==")