perf(streaming): item 3 bought nothing, item 5 removed dead weight -- both worth knowing

Two WORK-NEXT items, one null result and one confirmed removal. Item 4 untouched.

ITEM 3 -- CANCEL OBSOLETE WORK AND PRIORITISE THE FLOOR: NULL RESULT
Clean -nullrhi, diagnostics off, 800 cm/s, 200 m of travel:

                          before            after
  request->ready p95      0.369117 s        0.367612 s
  queue wait p95          0.066949 s        0.064483 s
  generation p95          0.287926 s        0.283642 s
  p95 travel distance     2.952938 m        2.940894 m
  obsolete aborts                 0                12

Flat. Aborting obsolete tiles, sorting from the true pawn position and prioritising the
occupied/next tile changed request-to-ready by 0.4%.

⭐ AND THE NULL RESULT IS ITSELF THE FINDING. Look at the split: queue wait is 65 ms of a
368 ms p95; generation is 284 ms. **The queue was never the problem, so reordering it
cannot help.** Only 12 tiles in a 200 m run were obsolete enough to abort. The floor is
late because generation is slow, not because work is badly ordered -- item 3 establishes
that by exclusion, which is worth more than the 0.4%.

The machinery is kept: it is correct, it costs nothing, and it will matter once
generation is fast enough for ordering to be the binding constraint.

ITEM 5 -- VERDICT CACHE REMOVED. It was pure overhead.
Clean moving-session audit:

  outer  calls/probes/hits    2,109 / 2,109 / 0
  nested calls/probes/hits   19,904 / 19,904 / 0
  enclosing hits                              0
  stores 15,877, evictions 15,365

⇒ It stored 15,877 proofs, evicted 15,365 of them, and hit ZERO times. A moving player
visits unique regions; the cache was filling and thrashing a 512-entry table under a
global lock for no benefit. Same-binary A/B: request p95 0.367645 vs 0.365978,
generation p95 0.285559 vs 0.285992 -- neutral within noise, so its cost was the lock and
the linear scans rather than time we can see.

Removed: the global cache, its lock, the entry table, the invalidation path, the
cache-only profiler fields and the synthetic probe. The proof classifier stays.

⚠️ I asked for this cache two days ago on the strength of a commandlet measurement that
re-visited the same region repeatedly. That access pattern is nothing like a moving
player, and I should have said so when specifying it.

VERIFIED BY ME: build 0 errors; export 0.563 / 0.565 / 0.566 s (35de59b was 0.545-0.563,
flat as expected); geometry SHA-256 b3e5f4c3..9b377 UNCHANGED; capability 20,830 /
10,909, connected.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012aheo2crrZmHuYtPpdY2Cb

Source/VoxelForge/Private/VoxelStartupTrace.cpp

@@ -98,8 +98,6 @@ namespace
         int32 AllAir = 0;
         int32 AllSolid = 0;
         int32 Mixed = 0;
-        int32 CacheHits = 0;
-        int32 RegionHits = 0;
         int64 Triangles = 0;
 
         for (const FTileSample& Sample : Samples)
@@ -110,8 +108,6 @@ namespace
             if (Sample.Verdict == 0) ++Mixed;
             else if (Sample.Verdict == 1) ++AllSolid;
             else if (Sample.Verdict == 2) ++AllAir;
-            if (Sample.bCacheHit) ++CacheHits;
-            if (Sample.bRegionHit) ++RegionHits;
             Triangles += Sample.Triangles;
             Request.Add(Sample.RequestToApplySeconds);
             Queue.Add(Sample.QueueWaitSeconds);
@@ -122,14 +118,14 @@ namespace
         }
 
         return FString::Printf(
-            TEXT("{\"count\":%d,\"empty\":%d,\"all_air\":%d,\"all_solid\":%d,\"mixed\":%d,\"cache_hits\":%d,\"region_hits\":%d,\"triangles\":%lld,"
+            TEXT("{\"count\":%d,\"empty\":%d,\"all_air\":%d,\"all_solid\":%d,\"mixed\":%d,\"triangles\":%lld,"
                  "\"request_apply_s\":{\"p50\":%s,\"p95\":%s,\"max\":%s},"
                  "\"queue_s\":{\"p50\":%s,\"p95\":%s,\"max\":%s},"
                  "\"generation_s\":{\"p50\":%s,\"p95\":%s,\"max\":%s},"
                  "\"classify_s\":{\"p50\":%s,\"p95\":%s,\"max\":%s},"
                  "\"mesh_s\":{\"p50\":%s,\"p95\":%s,\"max\":%s},"
                  "\"apply_s\":{\"p50\":%s,\"p95\":%s,\"max\":%s}}"),
-            Count, Empty, AllAir, AllSolid, Mixed, CacheHits, RegionHits, static_cast<long long>(Triangles),
+            Count, Empty, AllAir, AllSolid, Mixed, static_cast<long long>(Triangles),
             *Number(Percentile(Request, 0.50)), *Number(Percentile(Request, 0.95)), *Number(Maximum(Request)),
             *Number(Percentile(Queue, 0.50)), *Number(Percentile(Queue, 0.95)), *Number(Maximum(Queue)),
             *Number(Percentile(Generation, 0.50)), *Number(Percentile(Generation, 0.95)), *Number(Maximum(Generation)),
@@ -264,11 +260,10 @@ void RecordTile(const FTileSample& Sample)
     GState->Samples.Add(Sample);
     ++GState->TileRecordsWritten;
     WriteEventLocked(*GState, TEXT("tile"), FString::Printf(
-        TEXT("\"level\":%d,\"verdict\":%d,\"empty\":%d,\"cache_hit\":%d,\"region_hit\":%d,\"triangles\":%d,"
+        TEXT("\"level\":%d,\"verdict\":%d,\"empty\":%d,\"triangles\":%d,"
              "\"request_to_apply_s\":%s,\"queue_wait_s\":%s,\"worker_queue_s\":%s,\"result_queue_s\":%s,"
              "\"generation_s\":%s,\"classify_s\":%s,\"mesh_s\":%s,\"stream_s\":%s,\"apply_s\":%s"),
-        Sample.Level, Sample.Verdict, Sample.bEmpty ? 1 : 0,
-        Sample.bCacheHit ? 1 : 0, Sample.bRegionHit ? 1 : 0, Sample.Triangles,
+        Sample.Level, Sample.Verdict, Sample.bEmpty ? 1 : 0, Sample.Triangles,
         *Number(Sample.RequestToApplySeconds), *Number(Sample.QueueWaitSeconds),
         *Number(Sample.WorkerQueueSeconds), *Number(Sample.ResultQueueSeconds),
         *Number(Sample.GenerationSeconds), *Number(Sample.ClassifySeconds),