test: remove trivial, duplicate and content-value tests (#2721)

## Summary
Many tests proved a specific change when it landed but don't need to run on every CI build forever. This removes **202 test methods and 9 files: 313 test cases, 2,247 → 1,934**. UOContent.Tests drops from about 14s to about 5s locally.

Removed:
- **Tautologies.** Asserting a constant, a constructor readback or a trivial getter, or testing BCL behavior.
- **Exact duplicates** of a surviving test on the same code path.
- **Obsolete regressions** whose failure can no longer be expressed.
- **Game-content values** shard owners customize (era drop rates, loot and skill tables, single-creature tuning). Each customization would otherwise force a test fix.

## How it was decided
1. Every test was classified, with a reason, by a per-shard sweep over all 287 test files.
2. Each proposed deletion was then checked by a second, adversarial reviewer against the surviving tests and the production code.
3. Anything that was the only coverage of a separate code path was **kept**, even where it looked like a duplicate. Examples: the unsigned `SpanReader`/`SpanWriter` methods, the at-location versus bounds enumerators, null-map enumerables, the security filters, archive-journal state transitions. About 130 proposed deletions were rejected this way.

Whole files removed:
- `FishingTests`, apart from 3 tests: the map-edge scan, serpent cleanup, and SOS chest consumption. The SOS test now stops at the first chest instead of measuring a catch rate. The multi-million-cast rate simulations are gone.
- `LordOaksTests` and `MeerEnragedTests` (single-creature tests).
- `AutoArchiveHelperTests`, `JsonDiscoverableTypeAttributeTests`, `DecimalSerializationTests` and `EnumConversionTests` (tautologies, or tests of their own local helpers).
- `NetworkStatsTests`.
- `MigratedDataLoadTests` (a subset of `AllSpawnFilesLoadTests`).
- `SpawnerFixtureCapture`: a capture tool, not a test, and its `version == 12` assert can no longer pass. The `.bin` fixtures it produced stay.

## Tests
- Server.Tests: 811 pass.
- UOContent.Tests: 1,123 pass.

A follow-up PR, stacked on this one, fixes how the remaining tests behave: shared state, CI-vacuous tests, harness duplication.

Projects/Server.Tests/Tests/Maps/MultiEnumeratorTests.cs

@@ -88,13 +88,6 @@ public class MultiEnumeratorTests
         }
     }
 
-    [Fact]
-    public void MultiEnumerator_MapNullYieldsEmpty()
-    {
-        var enumerator = new Map.MultiBoundsEnumerable<BaseMulti>(null, Rectangle2D.Empty, false).GetEnumerator();
-        Assert.False(enumerator.MoveNext());
-    }
-
     [Fact]
     public void MultiEnumerator_ThrowsOnVersionChange()
     {
@@ -250,35 +243,6 @@ public class MultiEnumeratorTests
         }
     }
 
-    [Fact]
-    public void MultiSectorEnumerator_DeletedMultisAreSkipped()
-    {
-        var map = Map.Felucca;
-        var location = new Point3D(750, 750, 0);
-
-        var multis = new TestMulti[3];
-        try
-        {
-            multis[0] = CreateMulti(map, location);
-            multis[1] = CreateMulti(map, new Point3D(location.X + 1, location.Y, 0));
-            multis[2] = CreateMulti(map, new Point3D(location.X + 2, location.Y, 0));
-
-            multis[1].Delete();
-
-            var found = new List<BaseMulti>();
-            foreach (var multi in map.GetMultisInRange<BaseMulti>(location, 10))
-            {
-                found.Add(multi);
-            }
-
-            Assert.Equal(new[] { multis[0], multis[2] }, found);
-        }
-        finally
-        {
-            DeleteAll(multis);
-        }
-    }
-
     [Fact]
     public void MultiSectorEnumerator_MapNullYieldsEmpty()
     {
@@ -286,49 +250,6 @@ public class MultiEnumeratorTests
         Assert.False(enumerator.MoveNext());
     }
 
-    [Fact]
-    public void MultiSectorEnumerator_UsesDifferentPointOverloads()
-    {
-        var map = Map.Felucca;
-        var location = new Point3D(800, 800, 5);
-
-        var multis = new TestMulti[1];
-        try
-        {
-            multis[0] = CreateMulti(map, location);
-
-            // Test Point3D overload
-            var found1 = new List<BaseMulti>();
-            foreach (var multi in map.GetMultisInSector(location))
-            {
-                found1.Add(multi);
-            }
-
-            // Test (int, int) overload
-            var found2 = new List<BaseMulti>();
-            foreach (var multi in map.GetMultisInSector(location.X, location.Y))
-            {
-                found2.Add(multi);
-            }
-
-            // Test Point2D overload
-            var found3 = new List<BaseMulti>();
-            foreach (var multi in map.GetMultisInSector(new Point2D(location.X, location.Y)))
-            {
-                found3.Add(multi);
-            }
-
-            Assert.Single(found1);
-            Assert.Equal(multis[0], found1[0]);
-            Assert.Equal(found1, found2);
-            Assert.Equal(found1, found3);
-        }
-        finally
-        {
-            DeleteAll(multis);
-        }
-    }
-
     [Fact]
     public void MultiEnumerator_ZeroRangeReturnsOnlyCenter()
     {