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/Drivers/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT/TwinCATDriver.cs

@@ -404,17 +404,6 @@ public sealed class TwinCATDriver : IDriver, IReadable, IWritable, ITagDiscovery
     /// EnableControllerBrowse, which the universal browser's PatchForBrowse guarantees at open time.</summary>
     public bool SupportsOnlineDiscovery => true;
 
-    /// <inheritdoc />
-    /// <remarks>The authored tag's <c>Name</c> is its RawPath and its driver FullName
-    /// (<c>DiscoverAsync</c> emits <c>FullName: tag.Name</c>), directly comparable to the browsed
-    /// symbols' <c>InstancePath</c>.</remarks>
-    public IReadOnlyCollection<string>? AuthoredDiscoveryRefs =>
-        _tagsByRawPath.Values.Select(t => t.Name).ToArray();
-
-    /// <inheritdoc />
-    /// <remarks>True: <c>DiscoverAsync</c> emits browsed ADS symbols AND re-emits every authored tag.</remarks>
-    public bool DiscoveryStreamIncludesAuthoredTags => true;
-
     /// <inheritdoc />
     public async Task DiscoverAsync(IAddressSpaceBuilder builder, CancellationToken cancellationToken)
     {