feat(cli): historyread --events reads event history over the wire (lmxopcua#776)

Item 1 of #776 (the B2 over-the-wire ask): Client.CLI had no way to issue a
HistoryReadEvents. `historyread --events` now sends ReadEventDetails to an
event notifier and prints one line per event in select-clause order.
--fields picks the select clauses (default EventId, EventType, Time,
SourceName, Severity, Message, ConditionName (on ConditionType), SourceNode);
--of-type adds an OfType where-clause. --events is exclusive with --modified /
--aggregate, and --fields / --of-type require it.

Client.Shared gains IOpcUaClientService/ISessionAdapter.HistoryReadEventsAsync
(default-implemented as NotSupported for other implementations) backed by the
real session adapter through HistoryReadPaging, so continuation points are
followed up to --max and a Bad node status is surfaced, not printed as empty.

Tests: CLI tests over the fake service (default filter, --fields/--of-type
filter, option conflicts); an over-the-wire test drives the shared client's
event read against the in-process server — the default fields come back
non-null, OfType filters, an invalid where-clause is BadEventFilterInvalid.
The other #776 items are decisions and are left open.

Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV

docs/Client.CLI.md

@@ -196,7 +196,7 @@ The summary prints per-node counts across these buckets:
 
 ### historyread
 
-Reads historical data from a node. Supports raw history reads and aggregate (processed) history reads.
+Reads historical data from a node. Supports raw, aggregate (processed), modified-value and event history reads.
 `--start` and `--end` are parsed with `CultureInfo.InvariantCulture` and treated as UTC; supply
 them in ISO 8601 UTC form (`YYYY-MM-DDTHH:MM:SSZ`) for unambiguous behaviour across hosts.
 
@@ -221,6 +221,11 @@ otopcua-cli historyread -u opc.tcp://localhost:4840/OtOpcUa \
 otopcua-cli historyread -u opc.tcp://localhost:4840/OtOpcUa -U apikey -P otua_<keyId>_<secret> \
   -n "ns=2;s=Plant/Modbus/dev1/Speed" \
   --start "2026-01-15T00:00:00Z" --end "2026-01-16T00:00:00Z" --modified
+
+# Event (alarm) history from an event notifier, only LimitAlarmType events and their subtypes
+otopcua-cli historyread -u opc.tcp://localhost:4840/OtOpcUa \
+  -n "ns=3;s=Area1/Line1/Tank1" \
+  --start "2026-01-15T00:00:00Z" --end "2026-01-16T00:00:00Z" --events --of-type i=2955
 ```
 
 `--modified` sends `ReadRawModifiedDetails` with `IsReadModified = true` (OPC UA Part 11, Gitea #668) and prints one line per
@@ -229,6 +234,14 @@ recorded modification: the source timestamp, the **prior** value (`(none)` for a
 continuation points up to `--max`. A server on the `Gateway` backend (no modification trail) answers `BadHistoryOperationUnsupported`.
 `--modified` cannot be combined with `--aggregate`. See [Historian.md §Modified-value history](Historian.md#modified-value-history-part-11).
 
+`--events` sends `ReadEventDetails` (OPC UA Part 11 HistoryReadEvents, Gitea #776) to an **event notifier** — an equipment or device
+folder — and prints one ` | `-separated line per event, in `--fields` order. `--fields` takes comma-separated event field browse names
+(default `EventId,EventType,Time,SourceName,Severity,Message,ConditionName,SourceNode`; `ConditionName` is selected on `ConditionType`,
+every other name on `BaseEventType`); a field the event cannot supply prints as `-`, a byte string (`EventId`) as hex. `--of-type <NodeId>`
+adds an `OfType` where-clause (that event type and its subtypes, e.g. `i=2955` LimitAlarmType, `i=10637` OffNormalAlarmType). It follows
+continuation points up to `--max`. `--events` cannot be combined with `--modified` or `--aggregate`, and `--fields` / `--of-type` need
+`--events`. See [Historian.md §Read variants](Historian.md#read-variants).
+
 | Flag | Description |
 |------|-------------|
 | `-n` / `--node` | Node ID to read history for (required) |
@@ -238,6 +251,9 @@ continuation points up to `--max`. A server on the `Gateway` backend (no modific
 | `--aggregate` | Aggregate function: Average, Minimum, Maximum, Count, Start, End, StandardDeviation, TimeAverage, TimeAverage2, Total, Total2, Interpolative |
 | `--interval` | Processing interval in milliseconds for aggregates (default: 3600000) |
 | `--modified` | Read modified-value history (Part 11 `IsReadModified`) instead of raw samples |
+| `--events` | Read event history (Part 11 HistoryReadEvents) from an event notifier instead of raw samples |
+| `--fields` | With `--events`: comma-separated event fields to select (default `EventId,EventType,Time,SourceName,Severity,Message,ConditionName,SourceNode`) |
+| `--of-type` | With `--events`: keep only events of this type or a subtype (an `OfType` where-clause), e.g. `i=2955` |
 
 ### historyupdate