Add core simulation modules for owniverse mechanics

- Introduced `life_evolution.gd` to manage life evolution processes.
- Implemented `manual_production.gd` for handling production mechanics, including resource management and production steps.
- Created `object_batches.gd` to manage batches of objects, including scaling and appending batches.
- Developed `object_ledger.gd` for tracking physical amounts, available resources, and binding ownerships.
- Added `simulation_module.gd` as a base class for simulation modules, providing a weak reference to the world.
- Established `stellar_rules.gd` for managing stellar evolution and destruction mechanics.
- Introduced `universe_environment.gd` to calculate environmental parameters based on the current state of the universe.

tests/test_module_lifecycle.gd

@@ -0,0 +1,38 @@
+extends SceneTree
+
+var checks: int = 0
+var failures: int = 0
+
+func _initialize() -> void:
+    call_deferred("run")
+
+func check(condition: bool, message: String) -> void:
+    checks += 1
+    if not condition:
+        failures += 1
+        push_error(message)
+
+func run() -> void:
+    var World = load("res://world/owniverse/owniverse.gd")
+    var first = World.new()
+    var second = World.new()
+    var names: Array = ["batches", "ledger", "production", "automatic", "stellar", "life", "environment", "evolution"]
+    var references: Array = []
+    for name in names:
+        check(first.get(name) != second.get(name), "World has its own " + name)
+        check(first.get(name).world == first, "Module refers to its owner: " + name)
+        references.append(weakref(first.get(name)))
+    first.state.amount.H = 123.0
+    first.presentation.pending_amounts.H = 123.0
+    check(not second.state.amount.has("H") and second.presentation.pending_amounts.is_empty(), "State and pending presentation are isolated")
+    first.free()
+    for reference in references:
+        check(reference.get_ref() == null, "Module is released with its world")
+    check(second.evolution.world == second, "Other world remains usable")
+    var snapshot: Dictionary = second.state.duplicate(true)
+    second.evolute(NAN)
+    second.evolute(-1.0)
+    check(second.state == snapshot, "Entry point rejects invalid time deltas")
+    second.free()
+    print("Module lifecycle: %d checks, %d failures" % [checks, failures])
+    quit(1 if failures else 0)