Survival Stalker Spawn Egg

Implement only these approved requirements: - Create one neutral humanoid entity resembling a player, using the fixed biped model. It enters the world when the player joins; use default dimensions 0.9 wide and 1.4 high, health 20, movement speed 0.25, attack damage 2, armor 0, tracking range 8, pig sound family, archetype-appropriate default goals, and no natural spawning. - Create the survival_stalker_entity texture: A humanoid Minecraft-style entity resembling a generic player, with a weathered survival outfit and an unsettling, increasingly unstable expression. - Create the survival_stalker_spawn_egg texture: A Minecraft spawn egg icon themed around a humanoid survival stalker, with muted earth tones and ominous dark markings.