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/Network/NetStateSendBufferTests.cs

@@ -390,38 +390,6 @@ public class NetStateSendBufferTests
         }
     }
 
-    [Fact]
-    public void Send_WithPartialRemainder_GrowsAndCopiesFullPayload()
-    {
-        var ns = CreateAuthenticatedNetState(out var client);
-        var baseSize = ns._socket.SendBuffer.PhysicalSize;
-
-        try
-        {
-            var first = Pattern(baseSize / 2, 200);
-            var second = Pattern(baseSize / 2 + 1, 201);
-            var expected = new byte[first.Length + second.Length];
-            first.CopyTo(expected, 0);
-            second.CopyTo(expected, first.Length);
-
-            // Remainder too small for the second send
-            ns.Send(first);
-            ns.Send(second);
-
-            Assert.True(ns.Running);
-            Assert.Equal(string.Empty, ns._disconnectReason);
-            Assert.True(ns._socket.SendBuffer.PhysicalSize > baseSize);
-            Assert.True(ns._sendBufferGrown);
-
-            Assert.Equal(expected, ReadAll(client, expected.Length));
-        }
-        finally
-        {
-            ns.Dispose();
-            client.Close();
-        }
-    }
-
     [Fact]
     public void Send_WithSendInFlight_GrowsAndStreamStaysIntact()
     {
@@ -628,58 +596,4 @@ public class NetStateSendBufferTests
         // growth off; budget untouched
         Assert.Equal(1L, NetState.CoerceSendBufferGrowthBudget(1, sendBufferSize, sendBufferSize));
     }
-
-    [Fact]
-    public void CoerceMaxBufferSlabs_ClampsToOneSlabPerConnection()
-    {
-        var maxConnections = NetState.SocketManager.MaxSockets;
-
-        // fewer than one slab is meaningless
-        Assert.Equal(1, NetState.CoerceMaxBufferSlabs(0));
-        Assert.Equal(1, NetState.CoerceMaxBufferSlabs(-4));
-
-        // more slabs than connections cannot make a slab any smaller
-        Assert.Equal(maxConnections, NetState.CoerceMaxBufferSlabs(maxConnections * 2));
-
-        Assert.Equal(128, NetState.CoerceMaxBufferSlabs(128));
-    }
-
-    [Fact]
-    public void CoerceInitialBufferSlabs_ClampsToTheSlabCount()
-    {
-        var slabs = NetState.BasePoolSlabCount(128);
-        Assert.True(slabs > 1);
-
-        Assert.Equal(1, NetState.CoerceInitialBufferSlabs(0, slabs));
-        Assert.Equal(1, NetState.CoerceInitialBufferSlabs(-1, slabs));
-
-        // a pool never holds more slabs than it has
-        Assert.Equal(slabs, NetState.CoerceInitialBufferSlabs(slabs + 1, slabs));
-
-        Assert.Equal(4, NetState.CoerceInitialBufferSlabs(4, slabs));
-    }
-
-    [Fact]
-    public void Ring_RegisteredBufferTable_MatchesTheConfiguredSlabCount()
-    {
-        var manager = NetState.SocketManager;
-        var maxBufferSlabs = NetState.CoerceMaxBufferSlabs(ServerConfiguration.GetSetting("network.maxBufferSlabs", NetState.DefaultMaxBufferSlabs));
-
-        // A table smaller than this throws at manager construction. Connections start on the
-        // transport minimum until the game server promotes them, so the formula must count those too.
-        // Mirrors what production passes: the request, not the effective size the manager may coerce
-        // down to (RequiredRegisteredBuffers treats a non-zero request as a pool either way).
-        Assert.Equal(
-            RingSocketManager.RequiredRegisteredBuffers(
-                manager.MaxSockets,
-                NetState.SendBufferSize,
-                manager.MaxSendBufferSize,
-                manager.SendBufferGrowthBudget,
-                maxBufferSlabs,
-                IORingBuffer.MinimumSize,
-                IORingBuffer.MinimumSize
-            ),
-            NetState.Ring.MaxRegisteredBuffers
-        );
-    }
 }