chore(localdb): phase-2 DoD sweep

Build: 0 errors solution-wide, and 0 warnings from every project this branch
touches. The ~816 solution-wide warnings are pre-existing xUnit1051 /
OTOPCUA0001 / CS86xx in untouched driver + client test projects.

Tests: full solution run compared against a full run on a detached worktree at
the pre-branch baseline 2e46d054. The two failure SETS are identical -- all 13
tests, same names, zero new failures. Net +26 tests: +3 Core.AlarmHistorian
(drain gate), +6 Runtime (role view), +17 Host.IntegrationTests (migrator +
convergence). Set comparison rather than counts, because the suite carries
standing environment- and load-dependent failures a count would hide.

The greps found real drift Task 6 missed -- eight live sites still naming the
deleted SqliteStoreAndForwardSink, including the AdminUI /alarms/historian
panel text, which is user-visible, and a <see cref> in HistorianAdapterActor
that resolved to nothing without warning. All repointed at
LocalDbStoreAndForwardSink; CLAUDE.md's alarm-history paragraph now also
records the LocalDb buffer and the primary-gated drain, and drops DatabasePath
from the knob list. docs/AlarmTracking.md still promised an
AlarmHistorianOptions.Validate() startup warning for a relative DatabasePath
and an empty SharedSecret; both branches are gone, so it now says so.

Code references to AlarmHistorian:DatabasePath reduce to exactly two intentional
ones: AlarmSfLegacyMigrator.LegacyPathKey and its test. No `new SqliteConnection`
remains anywhere in Core.AlarmHistorian.

Recon doc gains the durable verification record: guard-deletion evidence for
both vacuous passes, the two exact-set replicated-table pins (both assert set
equality, so an added or a dropped registration fails), and the baseline test
comparison with a per-failure account of why each of the 13 is not this
branch's.

Stops here per the plan. Task 8's live gate needs explicit go-ahead; nothing on
this branch is to be merged.

Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.Tests/GatewayAlarmWriterFactoryTests.cs

@@ -7,7 +7,7 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.Tests;
 
 /// <summary>
 /// Alarm-write cutover seam test (T13). The Host's <c>AddAlarmHistorian</c> wiring drains the durable
-/// <c>SqliteStoreAndForwardSink</c> through this factory, so it must yield the gateway-backed writer —
+/// <c>LocalDbStoreAndForwardSink</c> through this factory, so it must yield the gateway-backed writer —
 /// sourcing the single gateway's connection from <see cref="ServerHistorianOptions"/> (endpoint/key/TLS),
 /// not the legacy Wonderware-shaped <c>AlarmHistorian</c> host/port. Built offline: the underlying
 /// channel dials lazily, so both the factory and the writer ctor perform no network I/O (a bogus,