fix(focas): ConcurrentDictionary for fixed-tree caches (05/STAB-5)

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FocasDriver.cs

@@ -1195,17 +1195,17 @@ public sealed class FocasDriver : IDriver, IReadable, IWritable, ITagDiscovery,
         ///     scale applied at <see cref="PublishAxisSnapshot"/>; integer fields
         ///     (feed rate, spindle speed) widen to double on store.
         /// </summary>
-        public Dictionary<string, double> LastFixedSnapshots { get; } = new(StringComparer.OrdinalIgnoreCase);
+        public ConcurrentDictionary<string, double> LastFixedSnapshots { get; } = new(StringComparer.OrdinalIgnoreCase);
         /// <summary>Gets or sets the last program information snapshot.</summary>
         public FocasProgramInfo? LastProgramInfo { get; set; }
         /// <summary>Gets or sets the cached first-axis dynamic snapshot — feeds Program/Number, /MainNumber, /Sequence.</summary>
         public FocasDynamicSnapshot? LastProgramAxisRef { get; set; }
         /// <summary>Gets the last timer values by timer kind.</summary>
-        public Dictionary<FocasTimerKind, FocasTimer> LastTimers { get; } = [];
+        public ConcurrentDictionary<FocasTimerKind, FocasTimer> LastTimers { get; } = new();
         /// <summary>Gets the last servo load percentages by servo name.</summary>
-        public Dictionary<string, double> LastServoLoads { get; } = new(StringComparer.OrdinalIgnoreCase);
+        public ConcurrentDictionary<string, double> LastServoLoads { get; } = new(StringComparer.OrdinalIgnoreCase);
         /// <summary>Gets the last spindle load percentages by spindle index.</summary>
-        public Dictionary<int, int> LastSpindleLoads { get; } = [];
+        public ConcurrentDictionary<int, int> LastSpindleLoads { get; } = new();
         /// <summary>
         ///     Gets or sets the per-axis position decimal-place figures fetched once at init via
         ///     <c>cnc_getfigure</c> (parallel to the axis-name list; index = axis). An auto figure