feat(input,ecs): #79 Input.axis_i directional int + #84 world bounds

#79 — Input.axis_i(neg,pos) -> int returns a -1/0/1 movement intent from the
multi-key device set, so WASD-to-movement needs no bool->int glue and feeds an
int mover directly (dx = Input.axis_i('a','d')).

#84 — a Bounds config entity (rect + policy, from ludic.core) drives the
engine-owned world-bounds system (LateUpdate): clamp / wrap / bounce (clamp +
flip Body velocity) / kill (despawn a body fully outside). Reads the Collider
size so the box stays inside; off by default, spliced only when Bounds is
declared (byte-identical otherwise). Adds World.despawn(e) — the by-id
reflective despawn (runs @OnDespawn + frees) via a new world_despawn intrinsic
whose @fn_world_despawn helper is emitted in emit_program's tail once a use is
seen (the g_uses_* prelude pattern), used by the kill policy and callable from
any system.

Examples input_movement + world_bounds. Full suite 112/0, goldens
byte-identical, fixpoint holds.

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

selfhost/backend/emit_call.ludic

@@ -224,6 +224,7 @@ function emit_ns_call(ns: pointer, meth: pointer, e: Node) -> Val {
     if (meth == "press")        { bare = "input_press";        push(labels, "key") }
     if (meth == "release")      { bare = "input_release";      push(labels, "key") }
     if (meth == "axis")         { bare = "input_axis";         push(labels, "neg"); push(labels, "pos") }
+    if (meth == "axis_i")       { bare = "input_axis_i";       push(labels, "neg"); push(labels, "pos") }   # #79 directional int (-1/0/1)
     if (meth == "vector")       { bare = "input_vector";       push(labels, "left"); push(labels, "right"); push(labels, "up"); push(labels, "down") }
     if (meth == "strength")     { bare = "input_strength";     push(labels, "action") }
     if (meth == "mouse_x")      { bare = "input_mouse_x" }
@@ -287,6 +288,7 @@ function emit_ns_call(ns: pointer, meth: pointer, e: Node) -> Val {
     if (meth == "count")         { bare = "world_count" }
     if (meth == "size")          { bare = "world_size" }
     if (meth == "spawn")         { bare = "world_spawn" }
+    if (meth == "despawn")       { bare = "world_despawn" }   # #84 — despawn an entity by id (runs @OnDespawn + frees)
     if (meth == "save")          { bare = "world_save" }
     if (meth == "load")          { bare = "world_load" }
     if (meth == "prop_id")       { bare = "world_prop_id" }

selfhost/backend/emit_decl.ludic

@@ -147,6 +147,7 @@ function emit_program() -> void {
   g_uses_panic = false
   g_uses_result = false
   g_uses_option = false
+  g_uses_world_despawn = false                   # #84: set when a world_despawn call is emitted (below)
   g_cov_lines = new []int
   g_cov_active = true
   loc_name = new []pointer;  loc_reg = new []pointer;  loc_ty = new []pointer;  loc_mut = new []int
@@ -184,6 +185,7 @@ function emit_program() -> void {
     i = 0
     while i < len(prog) { if prog[i].kind == N_MAIN { emit_main(prog[i]) };  i = i + 1 }
   } } }
+  if g_uses_world_despawn { emit_world_despawn_fn() }   # #84: @fn_world_despawn, after all World.despawn / esys_bounds-kill uses are seen
   if g_uses_loopback { emit_loopback() }         # built-in transport, after all net_send/net_poll uses are seen
   if g_uses_str { emit_str_prelude() }          # @fn_str_eq / @fn_str_concat, after all uses are seen
   if g_uses_intstr { emit_int_str() }           # @fn_int_str, for string(int) in interpolation

selfhost/backend/emit_intrin.ludic

@@ -13,6 +13,7 @@ function is_intrinsic(name: pointer) -> bool {
   if (name == "arg_count") or (name == "arg") or (name == "exit") { return true }
   if (name == "file_stderr") or (name == "file_stdout") { return true }
   if (name == "run") or (name == "getenv") { return true }
+  if (name == "world_despawn") { return true }          # #84 — despawn an entity by id from a system
   return false
 }
 # emit "  <r> = <rest>\n" and return r
@@ -56,6 +57,15 @@ function emit_intrinsic(name: pointer, e: Node) -> Val {
     emit("  call i32 @fclose(ptr ");  emit(f);  emit(")\n")
     return val("0", "void")
   }
+  # #84 — despawn an entity by id (runs its @OnDespawn hooks + frees the slot),
+  # callable from a system (esys_bounds kill) or as World.despawn(e). The helper
+  # @fn_world_despawn is emitted with the ECS defs when g_uses_world_despawn.
+  if (name == "world_despawn") {
+    g_uses_world_despawn = true                        # emit @fn_world_despawn in the tail (after all uses seen)
+    let ent = arg_code(e, 0)
+    emit("  call void @fn_world_despawn(i32 ");  emit(ent);  emit(")\n")
+    return val("0", "void")
+  }
   # print_str / print_int are the polymorphic `print(x)` builtin now (emit_call).
   if (name == "arg_count") { return val(emit_bind("load i32, ptr @L_argc"), "int") }
   if (name == "arg") {

selfhost/backend/game/emit_game.ludic

@@ -293,6 +293,37 @@ function emit_despawn_hooks() -> void {
   emit_despawn_all_fn()
 }
 
+# #84 — @fn_world_despawn(e): the runtime-callable despawn, used by the
+# world-bounds kill policy and World.despawn(e). Same per-kind @OnDespawn dispatch
+# as the `despawn` statement (emit_despawn) but reading a runtime %e, then the
+# entity-scoped-listener sweep and the slot free. Emitted from emit_program's tail
+# only when a world_despawn call was emitted (g_uses_world_despawn), after all uses
+# are seen — so a program that never despawns by id is byte-identical.
+function emit_world_despawn_fn() -> void {
+  emit("define void @fn_world_despawn(i32 %e) {\nentry:\n")
+  if len(g_ondespawn) > 0 {
+    let me = itoa(MAX_ENT)
+    emit("  %kp = getelementptr inbounds [");  emit(me);  emit(" x i32], ptr @L_kind, i32 0, i32 %e\n")
+    emit("  %k = load i32, ptr %kp\n")
+    var i = 0
+    while i < len(g_ondespawn) {
+      let mname = g_ondespawn[i].s
+      let si = itoa(i)
+      emit("  %c");  emit(si);  emit(" = icmp eq i32 %k, ");  emit(itoa(find_arch_id(mname)));  emit("\n")
+      emit("  br i1 %c");  emit(si);  emit(", label %hit");  emit(si);  emit(", label %next");  emit(si);  emit("\n")
+      emit("hit");  emit(si);  emit(":\n  call void @on_despawn_");  emit(mname);  emit("(i32 %e, i32 0)\n")   # reason = Despawned
+      let dev = `model_{mname}_despawn`
+      if (find_event(dev) != null) { emit("  call void @ev_");  emit(dev);  emit("(i32 %e, i32 0)\n") }
+      emit("  br label %next");  emit(si);  emit("\n")
+      emit("next");  emit(si);  emit(":\n")
+      i = i + 1
+    }
+  }
+  if len(g_events) > 0 { emit("  call void @ludic_sweep_entity(i32 %e)\n") }   # EV5: drop entity-scoped listeners
+  emit("  call void @L_free_entity(i32 %e)\n")
+  emit("  ret void\n}\n\n")
+}
+
 # LC1 "no silent deaths": at program shutdown every still-live entity's despawn
 # hook fires with reason Quit, so teardown that must run on exit is not skipped.
 # @L_despawn_all(reason) walks the live set and dispatches each entity by kind —