chore: organize solution into module folders (Core/Server/Drivers/Client/Tooling)

Group all 69 projects into category subfolders under src/ and tests/ so the
Rider Solution Explorer mirrors the module structure. Folders: Core, Server,
Drivers (with a nested Driver CLIs subfolder), Client, Tooling.

- Move every project folder on disk with git mv (history preserved as renames).
- Recompute relative paths in 57 .csproj files: cross-category ProjectReferences,
  the lib/ HintPath+None refs in Driver.Historian.Wonderware, and the external
  mxaccessgw refs in Driver.Galaxy and its test project.
- Rebuild ZB.MOM.WW.OtOpcUa.slnx with nested solution folders.
- Re-prefix project paths in functional scripts (e2e, compliance, smoke SQL,
  integration, install).

Build green (0 errors); unit tests pass. Docs left for a separate pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/Core/ZB.MOM.WW.OtOpcUa.Configuration.Tests/LiteDbConfigCacheTests.cs

@@ -0,0 +1,107 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Configuration.LocalCache;
+
+namespace ZB.MOM.WW.OtOpcUa.Configuration.Tests;
+
+[Trait("Category", "Unit")]
+public sealed class LiteDbConfigCacheTests : IDisposable
+{
+    private readonly string _dbPath = Path.Combine(Path.GetTempPath(), $"otopcua-cache-test-{Guid.NewGuid():N}.db");
+
+    public void Dispose()
+    {
+        if (File.Exists(_dbPath)) File.Delete(_dbPath);
+    }
+
+    private GenerationSnapshot Snapshot(string cluster, long gen) => new()
+    {
+        ClusterId = cluster,
+        GenerationId = gen,
+        CachedAt = DateTime.UtcNow,
+        PayloadJson = $"{{\"g\":{gen}}}",
+    };
+
+    [Fact]
+    public async Task Roundtrip_preserves_payload()
+    {
+        using var cache = new LiteDbConfigCache(_dbPath);
+        var put = Snapshot("c-1", 42);
+        await cache.PutAsync(put);
+
+        var got = await cache.GetMostRecentAsync("c-1");
+        got.ShouldNotBeNull();
+        got!.GenerationId.ShouldBe(42);
+        got.PayloadJson.ShouldBe(put.PayloadJson);
+    }
+
+    [Fact]
+    public async Task GetMostRecent_returns_latest_when_multiple_generations_present()
+    {
+        using var cache = new LiteDbConfigCache(_dbPath);
+        foreach (var g in new long[] { 10, 20, 15 })
+            await cache.PutAsync(Snapshot("c-1", g));
+
+        var got = await cache.GetMostRecentAsync("c-1");
+        got!.GenerationId.ShouldBe(20);
+    }
+
+    [Fact]
+    public async Task GetMostRecent_returns_null_for_unknown_cluster()
+    {
+        using var cache = new LiteDbConfigCache(_dbPath);
+        (await cache.GetMostRecentAsync("ghost")).ShouldBeNull();
+    }
+
+    [Fact]
+    public async Task Prune_keeps_latest_N_and_drops_older()
+    {
+        using var cache = new LiteDbConfigCache(_dbPath);
+        for (long g = 1; g <= 15; g++)
+            await cache.PutAsync(Snapshot("c-1", g));
+
+        await cache.PruneOldGenerationsAsync("c-1", keepLatest: 10);
+
+        (await cache.GetMostRecentAsync("c-1"))!.GenerationId.ShouldBe(15);
+
+        // Drop them one by one and count — should be exactly 10 remaining
+        var count = 0;
+        while (await cache.GetMostRecentAsync("c-1") is not null)
+        {
+            count++;
+            await cache.PruneOldGenerationsAsync("c-1", keepLatest: Math.Max(0, 10 - count));
+            if (count > 20) break; // safety
+        }
+        count.ShouldBe(10);
+    }
+
+    [Fact]
+    public async Task Put_same_cluster_generation_twice_replaces_not_duplicates()
+    {
+        using var cache = new LiteDbConfigCache(_dbPath);
+        var first = Snapshot("c-1", 1);
+        first.PayloadJson = "{\"v\":1}";
+        await cache.PutAsync(first);
+
+        var second = Snapshot("c-1", 1);
+        second.PayloadJson = "{\"v\":2}";
+        await cache.PutAsync(second);
+
+        (await cache.GetMostRecentAsync("c-1"))!.PayloadJson.ShouldBe("{\"v\":2}");
+    }
+
+    [Fact]
+    public void Corrupt_file_surfaces_as_LocalConfigCacheCorruptException()
+    {
+        // Write a file large enough to look like a LiteDB page but with garbage contents so page
+        // deserialization fails on the first read probe.
+        File.WriteAllBytes(_dbPath, new byte[8192]);
+        Array.Fill<byte>(File.ReadAllBytes(_dbPath), 0xAB);
+        using (var fs = File.OpenWrite(_dbPath))
+        {
+            fs.Write(new byte[8192].Select(_ => (byte)0xAB).ToArray());
+        }
+
+        Should.Throw<LocalConfigCacheCorruptException>(() => new LiteDbConfigCache(_dbPath));
+    }
+}