Update export presets, project version, and enhance civilization simulation rules

- Updated export path and version code in export_presets.cfg
- Changed project version in project.godot to 0.7.0
- Expanded simulation rules in simulation_rules.md to clarify resource management
- Improved testing framework in tests/README.md to include new civilization budget checks
- Added new tests for batch boundaries and civilization state transitions
- Enhanced civilization_state.gd with shared budget and transition logic
- Refactored owniverse.gd to enforce capacity during life batch initialization

tests/test_batch_boundaries.gd

@@ -0,0 +1,57 @@
+extends SceneTree
+const Clock = preload("res://world/owniverse/simulation_time.gd")
+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 fixture():
+    var world = load("res://world/owniverse/owniverse.gd").new()
+    var global: Node = root.get_node("Global")
+    for id in global.OwniverseEntities:
+        var entity = load("res://world/owniverse/owniverse_entity.gd").new(global.OwniverseEntities[id])
+        world.entities[id] = entity
+        world.state.amount[id] = 0.0
+        world.state.stats.total_amount[id] = 0.0
+        if entity.group_as != "":
+            world.state.amount[entity.group_as] = 0.0
+            world.state.stats.total_amount[entity.group_as] = 0.0
+    world.entities["N"].life_product = {}
+    world.entities["N"].product_per_year_type = "H"
+    world.entities["N"].product_per_year_amount = 10.0
+    world.entities["N"].auto = 0.0
+    world.state.amount.N = 1.0
+    return world
+
+func dispose(world) -> void:
+    for entity in world.entities.values():
+        entity.free()
+    world.free()
+
+func run() -> void:
+    var world = fixture()
+    world.state.batch_origins.LGRB = 10357034.80000000074505806
+    var boundary: float = 41215289.79999999701976776
+    for interval in [[boundary - 2.5, boundary + 2.25], [boundary, boundary + 2.0]]:
+        world.state.batches.LGRB = []
+        world._append_batch(world.state, "LGRB", 100.0, interval[0], interval[1])
+        var total: float = 0.0
+        var last: float = -INF
+        for batch: Dictionary in world.state.batches.LGRB:
+            total += batch.amount
+            check(batch.created_from > last, "Batch windows advance monotonically")
+            check(batch.created_to > batch.created_from, "Positive window duration")
+            check(batch.amount >= 0.0, "No negative batch amounts")
+            last = batch.created_from
+        check(total == 100.0, "Boundary correction preserves all objects")
+        check(world.state.batches.LGRB.size() <= 7, "Finite number of windows")
+    dispose(world)
+    print("Batch boundaries: %d checks, %d failures" % [checks, failures])
+    quit(0 if failures == 0 else 1)