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>

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Wonderware/Ipc/Framing.cs

@@ -0,0 +1,48 @@
+namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.Wonderware.Ipc;
+
+/// <summary>
+///     Length-prefixed framing constants for the Wonderware historian sidecar pipe protocol.
+///     Each frame on the wire is:
+///     <c>[4-byte big-endian length][1-byte message kind][MessagePack body]</c>.
+///     Length is the body size only; the kind byte is not part of the prefixed length.
+/// </summary>
+/// <remarks>
+///     Mirrors the Galaxy.Shared framing exactly so the same FrameReader/FrameWriter pattern
+///     works on both sides. The sidecar's protocol is independent — both the .NET 4.8 server
+///     side and the .NET 10 client (PR 3.4) carry their own copies of these constants and
+///     stay in sync via the round-trip test matrix.
+/// </remarks>
+public static class Framing
+{
+    public const int LengthPrefixSize = 4;
+    public const int KindByteSize = 1;
+
+    /// <summary>16 MiB cap protects the receiver from a hostile or buggy peer.</summary>
+    public const int MaxFrameBodyBytes = 16 * 1024 * 1024;
+}
+
+/// <summary>
+///     Wire identifier for each historian sidecar message. Values are stable — never reorder;
+///     append new contracts at the end. The .NET 10 client and the .NET 4.8 sidecar must
+///     agree on every value here.
+/// </summary>
+public enum MessageKind : byte
+{
+    Hello                       = 0x01,
+    HelloAck                    = 0x02,
+
+    ReadRawRequest              = 0x10,
+    ReadRawReply                = 0x11,
+
+    ReadProcessedRequest        = 0x12,
+    ReadProcessedReply          = 0x13,
+
+    ReadAtTimeRequest           = 0x14,
+    ReadAtTimeReply             = 0x15,
+
+    ReadEventsRequest           = 0x16,
+    ReadEventsReply             = 0x17,
+
+    WriteAlarmEventsRequest     = 0x20,
+    WriteAlarmEventsReply       = 0x21,
+}