revert(drivers): remove the periodic 5-minute device re-browse (#523)

Removes the tag-set drift detector shipped in e77c8a35. The design was sound
-- the tautology drivers were correctly gated out, and the structurally
undetectable "vanished" direction was declared rather than faked -- but none of
that is the objection. The feature browsed real plant equipment on a recurring
timer, at a frequency no operator could configure (the interval was a
constructor parameter with no appsettings key), and that outbound traffic was
never once observed against a real PLC, CNC or MTConnect Agent.

Removed: TagSetDrift/TagSetDriftDetector; DriverInstanceActor's drift timer,
tick message, Props/ctor parameter, gate, handler and leaf-collector;
ITagDiscovery.AuthoredDiscoveryRefs + .DiscoveryStreamIncludesAuthoredTags and
their four implementations; 14 tests.

Kept: ITagDiscovery.SupportsOnlineDiscovery (it predates this and drives the
universal browse picker), and the whole IRediscoverable consumption from
09a401b8 -- the driver tells us, we do not poll.

CONSEQUENCE, deliberately accepted: AbCip and FOCAS browse a live backend but
implement no IRediscoverable, so they now have NO tag-change signal at all -- a
PLC re-download is invisible until someone re-browses by hand. Recorded in
CLAUDE.md so the next reader does not have to rediscover it, along with the
shape to reach for if that coverage is wanted back (event-driven, or triggered
by a reconnect/deploy, not a wall-clock timer).

Runtime.Tests 476 pass / 13 skipped (skip set unchanged); FOCAS 275, TwinCAT
192, MTConnect 491, AbCip 342, Core.Abstractions 266 all green.

Claude-Session: https://claude.ai/code/session_015p7wGqy3YpZNCpDzTpGMKo

src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/ITagDiscovery.cs

@@ -38,32 +38,4 @@ public interface ITagDiscovery
     ///     See docs/plans/2026-07-15-universal-discovery-browser-design.md §5.
     /// </summary>
     bool SupportsOnlineDiscovery => false;
-
-    /// <summary>
-    ///     The device-native references this driver's <b>authored</b> tags bind to — the same vocabulary
-    ///     <see cref="DiscoverAsync"/> streams as <see cref="DriverAttributeInfo.FullName"/>. Comparing the
-    ///     two sets detects that the remote's tag set has drifted from what an operator authored.
-    ///     <para><b>Null means "I do not report this", and drift detection is skipped.</b> That is the
-    ///     default on purpose: an empty collection legitimately means "no tags authored, so everything
-    ///     discovered is new", and the two must not be confused. A driver opting in is asserting that its
-    ///     authored refs are directly comparable to what it discovers.</para>
-    ///     <para>Only consulted when <see cref="SupportsOnlineDiscovery"/> is true. For a driver that
-    ///     replays authored tags from config rather than browsing the backend, the comparison is a
-    ///     tautology — it would report "no drift" forever and read as reassurance.</para>
-    /// </summary>
-    IReadOnlyCollection<string>? AuthoredDiscoveryRefs => null;
-
-    /// <summary>
-    ///     True when <see cref="DiscoverAsync"/> re-emits this driver's <b>authored</b> tags into the same
-    ///     stream as the device-derived ones — which FOCAS, TwinCAT and AbCip all do, so the browse picker
-    ///     shows an operator their existing tags alongside what the device offers.
-    ///     <para><b>This makes one half of drift detection structurally undetectable.</b> If authored tags
-    ///     are always re-emitted then the discovered set always contains the authored set, so an authored tag
-    ///     that has VANISHED from the device can never appear missing. Declaring it here means the detector
-    ///     reports only what it can actually see, instead of reporting "nothing vanished" forever and reading
-    ///     as reassurance.</para>
-    ///     <para>False (the default) means the stream is purely device-derived — as MTConnect's is, built
-    ///     from the Agent's probe model — so both directions are detectable.</para>
-    /// </summary>
-    bool DiscoveryStreamIncludesAuthoredTags => false;
 }