perf(runtime): remove measured steady allocations

Eliminate boxed production surface-override enumeration, retain vital modifier projections until the enchantment registry mutates, and measure DAT font widths without allocating a captured delegate. Preserve exact hashes, spell stacking, and glyph advances with warmed zero-allocation tests.

Validated by the focused rendering, UI, and spell suites, a zero-error Release build, and 8,409 passing Release tests with five pre-existing skips.

Co-authored-by: Codex <codex@openai.com>

tests/AcDream.App.Tests/Rendering/CurrentRenderSceneOracleTests.cs

@@ -472,6 +472,33 @@ public sealed class CurrentRenderSceneOracleTests
             CurrentRenderSceneOracle.CreateSurfaceOverrideFingerprint(null));
     }
 
+    [Fact]
+    public void SurfaceOverrideFingerprint_DictionaryHotPathAllocatesNothing()
+    {
+        var overrides = new Dictionary<uint, uint>
+        {
+            [0x0800_0001] = 0x0500_0011,
+            [0x0800_0002] = 0x0500_0012,
+            [0x0800_0003] = 0x0500_0013,
+        };
+        RenderSceneHash128 expected =
+            CurrentRenderSceneOracle.CreateSurfaceOverrideFingerprint(
+                overrides);
+        RenderSceneHash128 actual = default;
+        long before = GC.GetAllocatedBytesForCurrentThread();
+
+        for (int iteration = 0; iteration < 10_000; iteration++)
+        {
+            actual =
+                CurrentRenderSceneOracle.CreateSurfaceOverrideFingerprint(
+                    overrides);
+        }
+
+        long allocated = GC.GetAllocatedBytesForCurrentThread() - before;
+        Assert.Equal(expected, actual);
+        Assert.Equal(0, allocated);
+    }
+
     private static CurrentRenderProjectionFingerprint CaptureSingle(
         WorldEntity entity,
         uint landblockId,