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>

scripts/smoke/seed-abcip-smoke.sql

@@ -1,7 +1,7 @@
 -- AB CIP e2e smoke seed — closes #211 (umbrella #209).
 --
 -- One-cluster seed pointing at the ab_server ControlLogix fixture
--- (`docker compose -f tests/ZB.MOM.WW.OtOpcUa.Driver.AbCip.IntegrationTests/Docker/docker-compose.yml --profile controllogix up -d`).
+-- (`docker compose -f tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip.IntegrationTests/Docker/docker-compose.yml --profile controllogix up -d`).
 -- Publishes a single `TestDINT:DInt` tag under NodeId `ns=<N>;s=TestDINT`
 -- (ab_server seeds this tag by default).
 --
@@ -124,5 +124,5 @@ PRINT 'Next steps:';
 PRINT '  1. Set src/.../Server/appsettings.json Node:NodeId = "abcip-smoke-node"';
 PRINT '                                          Node:ClusterId = "abcip-smoke"';
 PRINT '  2. docker compose -f tests/.../AbCip.IntegrationTests/Docker/docker-compose.yml --profile controllogix up -d';
-PRINT '  3. dotnet run --project src/ZB.MOM.WW.OtOpcUa.Server';
+PRINT '  3. dotnet run --project src/Server/ZB.MOM.WW.OtOpcUa.Server';
 PRINT '  4. ./scripts/e2e/test-abcip.ps1 -BridgeNodeId "ns=2;s=TestDINT"';