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_frame_evolution.gd

@@ -35,7 +35,7 @@ func run():
     direct = fixture()
     sliced = fixture()
     var initial_h: Variant = sliced.state.amount.H
-    sliced.evolute_frame(1.0 / 60.0, self)
+    sliced.evolute_frame(0.2, self)
     check(sliced.frame_busy, "Heavy transaction yields before publishing")
     check(E.eq(sliced.state.time.year, 0), "Published clock stays at completed transaction")
     sliced.request_production("H", 1, true)
@@ -45,7 +45,7 @@ func run():
     sliced.speed = 3
     check(sliced.speed == 3 and sliced.state.speed == 6, "Speed change is visible and cannot mutate an unfinished transaction")
     while sliced.frame_busy: await process_frame
-    direct.evolute(1.0 / 60.0)
+    direct.evolute(0.2)
     direct.production.produce_hs("H", 1)
     direct.speed = 3
     check(E.eq(direct.state, sliced.state), "Queued action and speed change survive publication")
@@ -60,7 +60,7 @@ func run():
     dispose(direct)
     dispose(sliced)
     var original = fixture()
-    original.evolute_frame(1.0 / 60.0, self)
+    original.evolute_frame(0.2, self)
     original.request_production("H", 123, true)
     original.evolute_frame(0.01, self)
     original.speed = 3
@@ -84,7 +84,7 @@ func run():
     dispose(resumed)
     dispose(expected)
     var cancelled = fixture()
-    cancelled.evolute_frame(0.133333333333, self)
+    cancelled.evolute_frame(0.2, self)
     check(cancelled.frame_busy, "Cancellation fixture has suspended work")
     var budget_ref: RefCounted = cancelled.frame_budget
     dispose(cancelled)
@@ -96,25 +96,26 @@ func run():
     invalid.evolute(1e308)
     check(not invalid.frame_busy and invalid.frame_clock.is_empty() and E.eq(before, invalid.state), "Overflowing elapsed float cannot enter either clock API")
     dispose(invalid)
-    var adaptive = fixture()
-    adaptive.frame_clock = Clock.advance(adaptive.state.time, 10.0, 6)
-    var debt_clock: Dictionary = adaptive.frame_clock.duplicate(true)
-    check(adaptive.update_frame_step() == 0.2, "Growing debt increases step to 0.2 seconds")
-    check(adaptive.update_frame_step() == 0.5, "Large debt increases step to bounded 0.5 seconds")
-    check(adaptive.update_frame_step() == 0.5 and E.eq(adaptive.frame_clock, debt_clock), "Maximum step preserves requested time")
-    adaptive.frame_clock = Clock.advance(adaptive.state.time, 0.3, 6)
-    check(adaptive.update_frame_step() == 0.5, "Hysteresis keeps step between thresholds")
-    adaptive.frame_clock = Clock.advance(adaptive.state.time, 0.05, 6)
-    check(adaptive.update_frame_step() == 0.2, "Small debt reduces step")
-    check(adaptive.update_frame_step() == 0.1, "Caught-up simulation returns to base step")
-    adaptive.frame_clock = Clock.advance(adaptive.state.time, 0.15, 6)
-    adaptive._frame_cost_ratio = 1.1
-    check(adaptive.update_frame_step() == 0.2, "Measured slow transactions increase step before two-step debt")
-    adaptive.frame_clock = Clock.advance(adaptive.state.time, 0.05, 6)
-    adaptive.speed = 3
-    check(adaptive.update_frame_step() == 1.0 / 60.0, "Low speeds retain 60 Hz scheduling")
-    adaptive.speed = 6
-    check(adaptive.update_frame_step() == 0.1, "Speed switch resets adaptive step")
-    dispose(adaptive)
+    for selected_speed in range(1, 7):
+        var scheduled = fixture()
+        scheduled.speed = selected_speed
+        scheduled.evolute_frame(0.1, self)
+        check(not scheduled.frame_busy and scheduled.frame_commits == 0, "Wait for a full step at speed %d" % selected_speed)
+        scheduled.evolute_frame(0.1, self)
+        while scheduled.frame_busy: await process_frame
+        var cadence_clock: Dictionary = Clock.advance({"datetime": 0, "year": 0}, 0.2, selected_speed)
+        check(scheduled.frame_commits == 1 and E.eq(scheduled.state.time, cadence_clock), "One complete 0.2 second cycle at speed %d" % selected_speed)
+        scheduled.evolute_frame(0.0, self)
+        check(not scheduled.frame_busy and scheduled.frame_commits == 1, "No extra cycle without elapsed time")
+        dispose(scheduled)
+    var behind = fixture()
+    behind.evolute_frame(1.0, self)
+    while behind.frame_busy: await process_frame
+    check(E.eq(behind.state.time.datetime, 20000) and E.eq(behind.frame_clock.datetime, 100000), "Debt keeps the fixed step and preserves all requested time")
+    for cycle in 4:
+        behind.evolute_frame(0.0, self)
+        while behind.frame_busy: await process_frame
+    check(behind.frame_commits == 5 and E.eq(behind.state.time, behind.frame_clock), "One second is processed in exactly five full cycles")
+    dispose(behind)
     print("Frame evolution: %d checks, %d failures" % [checks, failures])
     quit(1 if failures else 0)