Add optional Lua scripting module, examples, and validation

examples/lua/Scripts/player.lua

@@ -0,0 +1,47 @@
+local Player = faset.behavior {
+    id = "example.lua_player",
+    version = 1,
+    name = "Lua Player",
+    fields = {
+        move_speed = {
+            name = "Move speed", type = "number", default = 5,
+            min = 0, max = 30, units = "m/s"
+        },
+        jump_speed = {
+            name = "Jump speed", type = "number", default = 7,
+            min = 0, max = 20, units = "m/s"
+        }
+    }
+}
+
+function Player:on_start()
+    self.state.origin = self.entity:transform()
+    self.state.jumps = 0
+    faset.log("Lua player ready: A/D move, Space jump, E reset")
+end
+
+function Player:fixed_update(delta)
+    local input = faset.input()
+    if input.interact_pressed then
+        self.entity:teleport(self.state.origin)
+        self.entity:set_velocity { x = 0, y = 0, z = 0 }
+        self.state.jumps = 0
+        return
+    end
+
+    local velocity = self.entity:velocity()
+    velocity.x = input.horizontal * self.fields.move_speed
+    if input.jump_pressed and self.entity:is_grounded() then
+        velocity.y = self.fields.jump_speed
+        self.state.jumps = self.state.jumps + 1
+        faset.log("Jump", self.state.jumps)
+    end
+    self.entity:set_velocity(velocity)
+
+    if self.entity:transform().position.y < -10 then
+        self.entity:teleport(self.state.origin)
+        self.entity:set_velocity { x = 0, y = 0, z = 0 }
+    end
+end
+
+return Player