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/README.md

@@ -63,7 +63,9 @@ live driver. The factory-wiring block that originally gated stages
 Live-boot verification:
 
 - **Galaxy** — 7/7 stages (read / write / subscribe / alarms / history)
-  against a real Galaxy + `OtOpcUaGalaxyHost` on this dev box.
+  against a real Galaxy via the in-process `GalaxyDriver` →
+  `mxaccessgw` (gRPC). PR 7.2 retired the legacy `OtOpcUaGalaxyHost`
+  out-of-process driver path.
 - **AB CIP, S7** — 5/5 stages each under task #220 against the
   `ab_server` + `python-snap7` fixtures.
 - **AB Legacy** — 5/5 stages under task #222 against `ab_server` SLC500
@@ -155,7 +157,7 @@ section to skip it.
 | Modbus | — | **PASS** (pymodbus fixture) |
 | AB CIP | — | **PASS** (ab_server fixture) |
 | AB Legacy | — | **PASS** (ab_server SLC500/MicroLogix/PLC-5 profiles; `/1,0` cip-path required for the Docker fixture) |
-| Galaxy | — | **PASS** (requires OtOpcUaGalaxyHost + a live Galaxy; 7 stages including alarms + history) |
+| Galaxy | — | **PASS** (requires mxaccessgw running + a live Galaxy; 7 stages including alarms + history; PR 7.2 retired the legacy OtOpcUaGalaxyHost path) |
 | S7 | — | **PASS** (python-snap7 fixture) |
 | FOCAS | `FOCAS_TRUST_WIRE=1` | **SKIP** (no public simulator — task #222 lab rig) |
 | TwinCAT | `TWINCAT_TRUST_WIRE=1` | **SKIP** by default; features **validated** against the TCBSD VM fixture — set the env var to run |