Refactor Owniverse modules for quantity mathematics and entity catalog

- Introduced `quantity_math.gd` for arithmetic operations including allocation, normalization, and accumulation of quantities without scene tree dependencies.
- Created `entity_catalog.gd` to manage entity definitions, groups, and event indexes, ensuring separation from simulation state and UI.
- Implemented `item_presentation.gd` for read-only projections of simulation state, handling amounts and unlock conditions for UI elements.
- Updated `civilization_evolution.gd` and `civilization_state.gd` to utilize new quantity math functions, improving code clarity and maintainability.
- Enhanced tests in `test_quantity_catalog.gd` to validate new functionality and ensure correctness of mathematical operations.
- Revised documentation to reflect changes in module structure and functionality.

tests/test_life_icons.gd

@@ -33,6 +33,23 @@ func run() -> void:
     check(counts["C0.0"] == 3.0 and counts.C0 == 3.0 and counts.Planet == 19.0, "Civilization detail does not double the planetary total")
     check(world.get_item_amounts(true).EON1 == 12.0 and world.get_item_amounts(true).LP == 16.0, "Historical counts retain individual and aggregate values")
     check(world.state == before, "Presentation does not modify simulation state")
+    var pending: Array = ["EON1", "EON2", "EON3", "C0.0"]
+    var pending_before: Array = pending.duplicate()
+    var decision: Dictionary = world.presentation.unlocks(world.state, world.catalog, pending)
+    check(decision.remaining == ["EON3"], "Only unmet requirements remain pending")
+    for id in ["EON1", "EON2", "LP", "C0.0", "C0"]:
+        check(decision.visible.has(id), "Unlock projection includes detail and alias: " + id)
+    check(pending == pending_before and world.state == before, "Unlock evaluation leaves inputs untouched")
+    var snapshot: Dictionary = world.items_to_update.duplicate()
+    world.defer_item_updates = true
+    world.state.amount.EON1 += 1.0
+    world.refresh_item_amounts()
+    check(world.item_amounts_dirty and world.items_to_update == snapshot, "Deferred refresh retains pending snapshot")
+    world.refresh_item_amounts(true)
+    check(not world.item_amounts_dirty and world.items_to_update.EON1 == 13.0, "Forced refresh publishes latest amounts")
+    world.state.amount.EON1 -= 1.0
+    world.defer_item_updates = false
+    world.refresh_item_amounts()
     for id in ["EON1", "EON2", "LP", "C0.0", "C0"]:
         check(stage.owniverse_items[id].visible, "Unlock both levels: " + id)
         check(stage.owniverse_items[id].description.text != "", "Populate the icon counter: " + id)