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_coarse_generations.gd

@@ -53,7 +53,7 @@ func run():
             check(E.eq(physical.get("C0.1", 0), 38300), "C0.1 attempts evolution once")
             check(E.eq(physical.get("C0.2", 0), 700), "C0.1 successor does not immediately attempt again")
         else:
-            check(world.profile.civilization_transitions[1] == 1, "Ethical civilization is processed only once per birth bucket")
+            check(world.profile.civilization_flow_plan[1] == 1, "Ethical civilization uses one continuous interval plan")
         var before: Dictionary = world.state.duplicate(true)
         world.evolution.evolute_to_datetime(10000)
         check(E.eq(world.state, before), "Repeating completed clock does not repeat transitions")