PR 7.2 — Retire legacy Galaxy projects + service

Matrix-gate satisfied (14 passed / 1 skipped / 0 failed on 2026-04-30
per docs/v2/Galaxy.ParityMatrix.md). Galaxy access flows through the
in-process GalaxyDriver → mxaccessgw exclusively. Legacy infrastructure
deleted in this commit:

Source projects (6):
- src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Host         (.NET 4.8 x86 + MXAccess COM)
- src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Proxy        (in-process pipe client)
- src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared       (pipe-IPC contracts)
- tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Host.Tests
- tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Proxy.Tests
- tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared.Tests

Test projects with no consumer after legacy retired (3):
- tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.E2E         (drove Galaxy.Host EXE)
- tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.ParityTests (drove both backends)
- tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.TestSupport (only consumed by Host/Proxy tests)

Edits:
- ZB.MOM.WW.OtOpcUa.slnx: drop nine project entries
- Server.csproj: drop Driver.Galaxy.Proxy ProjectReference
- Server/Program.cs: drop GalaxyProxyDriverFactoryExtensions.Register
  + the parallel-registration comment block; only GalaxyDriverFactoryExtensions
  registers now under DriverType "GalaxyMxGateway"
- Install-Services.ps1: rewrite to drop OtOpcUaGalaxyHost service install +
  the GalaxySharedSecret/ZbConnection/GalaxyClientName/GalaxyPipeName/
  AvevaServiceDependencies/MxAccessInitialConnect* parameters that only
  applied to the legacy host. Adds a closing note pointing operators at
  the separate mxaccessgw install
- Uninstall-Services.ps1: keep OtOpcUaGalaxyHost in the cleanup loop so
  pre-7.2 rigs upgrade-uninstall cleanly, plus add OtOpcUaWonderwareHistorian
- scripts/e2e/test-galaxy.ps1: deleted (drove the legacy E2E)
- scripts/e2e/e2e-config.sample.json: rewrite the galaxy section comment
  to reflect the GalaxyMxGateway-only path
- scripts/e2e/README.md: drop OtOpcUaGalaxyHost references
- scripts/compliance/phase-7-compliance.ps1: drop Galaxy.Shared
  HistorianAlarms* checks (those contracts moved to
  Driver.Historian.Wonderware.Client in PR 3.4)

Live state: OtOpcUaGalaxyHost Windows service stopped + removed via
NSSM before this commit. The dev box's Galaxy access is now exclusively
through the running mxaccessgw (separate repo).

Stays out of scope for PR 7.2 (PR 7.3 territory):
- CLAUDE.md Galaxy section rewrite
- mxaccess_documentation.md deletion
- Memory entries for the now-retired Galaxy.Host service

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

scripts/e2e/e2e-config.sample.json

@@ -50,7 +50,7 @@
     },
 
     "galaxy": {
-        "$comment": "Galaxy (MXAccess) driver. Has no per-driver CLI — all stages go through otopcua-cli against the published NodeIds. Seven stages: probe / source read / virtual-tag bridge / subscribe-sees-change / reverse write / alarm fires / history read. PR 7.1 default-flipped backend to GalaxyMxGateway (in-process .NET 10 driver over mxaccessgw gRPC at http://localhost:5120 by default — override via the DriverInstance row's DriverConfig). Pre-flip rigs running the legacy 'Galaxy' DriverType still need OtOpcUaGalaxyHost running + seed-phase-7-smoke.sql applied with a real Galaxy attribute substituted into dbo.Tag.TagConfig.",
+        "$comment": "Galaxy (MXAccess) driver. Has no per-driver CLI — all stages go through otopcua-cli against the published NodeIds. Seven stages: probe / source read / virtual-tag bridge / subscribe-sees-change / reverse write / alarm fires / history read. The driver is now the in-process GalaxyDriver (DriverType = 'GalaxyMxGateway') talking gRPC to a separately-installed mxaccessgw at http://localhost:5120 by default — override via the DriverInstance row's DriverConfig. PR 7.2 retired the legacy 'Galaxy' DriverType + OtOpcUaGalaxyHost service.",
         "sourceNodeId": "ns=2;s=p7-smoke-tag-source",
         "virtualNodeId": "ns=2;s=p7-smoke-vt-derived",
         "alarmNodeId": "ns=2;s=p7-smoke-al-overtemp",