Implement civilization flow mechanics and profiling for resource allocation

- Added `civilization_flow.gd` to manage continuous expected flows and resource allocation within civilizations.
- Introduced `allocate_profiled` and `whole_quotas` functions in `quantity_math.gd` for precise stock allocation based on float shares.
- Enhanced `credit` logic in `object_ledger.gd` to handle production remainders more effectively.
- Updated `append_batch` in `object_batches.gd` to prevent batch creation for invalid IDs.
- Introduced `ratio_approx` function in `exact.gd` for better handling of float profiles.
- Added a benchmark script `benchmark_civilization_flows.gd` to evaluate the performance of civilization flow mechanics.
- Refactored various functions to improve clarity and efficiency in handling resource flows and allocations.

tests/test_civilization_state.gd

@@ -79,7 +79,8 @@ func run() -> void:
         row.colonization = "0"
     world.state.binds.RD = {"C1.9": 10}
     world.state.batches["C1.9"] = [{"amount": 10, "start_year": 1, "end_year": 1}]
-    world.evolution.evolve_batches(world.state, 1)
+    global.CivilizationRules["C1.9"].span = E.of("0.001")
+    world.civilization_flow.evolve(world.state, 0, 1)
     check((E.eq(world.state.amount["C2.0"], 10) and E.eq(world.state.binds.RD.get("C2.0", 0), 0)), "Space successor does not inherit planetary binding")
     dispose(world)
     var capacity = load("res://world/owniverse/civilization_state.gd")
@@ -133,7 +134,7 @@ func run() -> void:
         row.colonization = "0"
     world.state.binds.RD = {"C1.9": 5}
     world.state.batches["C1.9"] = [{"amount": 5, "start_year": 1, "end_year": 1}]
-    world.evolution.evolve_batches(world.state, 1)
+    world.civilization_flow.evolve(world.state, 0, 1)
     check((E.eq(world.state.amount["C2.0"], 2) and E.eq(world.state.binds.RD["C1.9"], 3)), "Unfunded transition retains the original planetary civilization")
     dispose(world)
     print(("Civilization state: %d checks, %d failures" % [checks, failures]))