v3(focas): adopt Modbus RawTagEntry exemplar (multi-device)

- Rename FocasEquipmentTagParser -> FocasTagDefinitionFactory; TryParse ->
  FromTagConfig(tagConfig, rawPath, out def). Drop leading-{ heuristic + the
  deviceHostAddress blob key; def.Name = rawPath. Add inverse ToTagConfig.
  writable: absent -> read-only, explicit true honoured (note preserved).
- FocasDriverOptions.Tags -> RawTags (IReadOnlyList<RawTagEntry>).
- FocasDriver: _tagsByRawPath (Ordinal); byName-only resolver; build table from
  RawTags via FromTagConfig; multi-device routing threads RawTagEntry.DeviceName
  -> ResolveDeviceHost match against options.Devices -> def.DeviceHostAddress
  (TODO v3 WaveC: live host from Device row DeviceConfig). Tolerant per-tag
  skip+log (mapper/address/matrix miss -> BadNodeIdUnknown); unknown device
  fails init fast.
- Factory: bind List<RawTagEntry> RawTags; retire FocasTagDto/ParseDataType.
- CLI FocasCommandBase.BuildOptions -> RawTags via ToTagConfig + DeviceName.
- Tests: FocasRawTags helper; migrate Tags= -> RawTags=; rename parser tests to
  FromTagConfig; rewrite retired blob-ref tests (equipment-tag/capability-gate/
  resolve-host) onto authored RawPath. 272 driver + 52 CLI green.

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Tests/FocasConnectBackoffTests.cs

@@ -17,7 +17,7 @@ public sealed class FocasConnectBackoffTests
     private static FocasDriverOptions Options(bool probeEnabled) => new()
     {
         Devices = [new FocasDeviceOptions("focas://10.0.0.5:8193")],
-        Tags = [new FocasTagDefinition("R", "focas://10.0.0.5:8193", "R100", FocasDataType.Byte)],
+        RawTags = [FocasRawTags.Entry(new FocasTagDefinition("R", "focas://10.0.0.5:8193", "R100", FocasDataType.Byte))],
         Probe = new FocasProbeOptions
         {
             Enabled = probeEnabled,