R1.11 DelTep capture + R1.3/R1.4/R1.12/R1.13 bounded out

DelTep (extended-property delete) — wire format captured + serializer
golden-proven, but live delete is server-blocked and NOT exposed publicly:
- Captured the DelTep inBuff via a cross-session trick (harness add-tep gains
  --tep-skip-add + read-for-sync before --tep-delete; Capture-DeleteTagExtended
  Properties.ps1 / decode-del-tep-capture.py). Layout = same group framing as
  AddTEx but property-name-only (no 0x43 value) + 0x00 group trailer.
- SerializeDeleteRequest + 4 golden tests pin the server-accepted buffer.
- A decisive experiment shows SDK-added properties ARE deletable (the native
  client read-syncs and deletes one), so SDK-add is complete; the SDK's own
  DelTep is rejected by CHistStorage::DeleteTagExtendedProperties even with
  byte-identical inBuff, matching mode/handle, GetTgByNm+GetTepByNm prime, open
  channel, and 60s retries. Root cause: the native multiplexes services over one
  connection (per-connection working set); the SDK's per-service WCF channels
  don't reproduce it. Kept as documented-but-blocked internal orchestrator path;
  no public HistorianClient delete API.

Bounded out with evidence (no code; docs + roadmap + probe):
- R1.12 localized-property write — no op on 2020 (mirror of R1.6); no
  *LocalizedPropert*/TagLocalized* symbol in any current/*.dll.
- R1.13 non-analog tag create — GATED; native AddTag rejects every non-analog
  type client-side (ValidationFailed, before any WCF op): SingleByteString,
  DoubleByteString, Int1 all fail, Float works. No Discrete type in the native
  enum, no TagType setter. No wire request to capture.
- R1.3 timezone + R1.4 EventStorageMode — re-confirmed 2023R2/gRPC-only from
  the Runtime DB schema (no timezone param, no EventStorageMode anywhere) and a
  parameter-op probe (GetSystemParameter + GETRP return null/throw for every
  candidate; only HistorianVersion works).

238 unit tests pass; full solution builds with 0 warnings.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC

src/AVEVA.Historian.Client/HistorianClient.cs

@@ -201,6 +201,15 @@ public sealed class HistorianClient : IAsyncDisposable
         return AddTagExtendedPropertiesAsync(tag, [new HistorianTagExtendedProperty(name, value ?? string.Empty)], cancellationToken);
     }
 
+    // Extended-property DELETE (DelTep) is intentionally NOT exposed publicly. Its wire format is
+    // captured and the serializer (HistorianTagExtendedPropertyProtocol.SerializeDeleteRequest) is
+    // golden-verified against a server-accepted buffer, but the SDK cannot yet make the 2020 server
+    // accept the delete: the server's CHistStorage::DeleteTagExtendedProperties consults a
+    // per-connection working set that the native client populates by multiplexing GetTepByNm and
+    // DelTep over ONE connection, which the SDK's per-service WCF channels don't reproduce. See the
+    // documented-but-blocked path in HistorianWcfTagWriteOrchestrator and
+    // docs/reverse-engineering/wcf-add-tag-extended-properties.md §Delete.
+
     /// <summary>
     /// Creates or updates the named tag in the Historian Runtime database via
     /// <c>EnsureTags2</c>. Currently only <see cref="HistorianDataType.Float"/> is