rnd(M03): extract render budget scheduler

RENDER.md

@@ -903,6 +903,22 @@ $exe = Join-Path $env:TEMP 'godot-4.6.1-openwc\Godot_v4.6.1-stable_win64.exe'
 - Cache versions, quality profiles, queue priority and visible rendering rules
   are unchanged by the extraction.
 
+## 2026-07-16 RenderBudgetScheduler Extraction
+
+- The scene-free `RenderBudgetScheduler` now owns the per-frame counters for 16
+  named renderer operation lanes. It owns no queue, task, cache, Node or RID.
+- `StreamingWorldLoader` snapshots its existing exported limits once per process
+  frame and asks for a boolean permit immediately before each historically
+  budgeted operation.
+- Chunk removals and creations intentionally share one `chunk_geometry` lane;
+  the existing removal-first drain order and combined limit are preserved.
+- Loader teardown cancels permit issuance before waiting for asynchronous work.
+  Existing worker/result staleness checks and resource cleanup remain unchanged.
+- Asset-free contracts cover exact bounds, independent/shared lanes, frame reset,
+  invalid inputs, terminal cancellation, detached diagnostics and hot-path timing.
+- Defaults, quality presets, queue order, cache versions and visible rendering
+  rules are unchanged. Asset-backed p95/p99 comparison remains required.
+
 ## Practical Rule For Future Work
 
 If something improves quality but creates visible hitch, it is not done. Move it to bake/cache/background work, split finalization over frames, or prewarm it before the player can see it.