fix(driver-cli-common): resolve Medium code-review finding (Driver.Cli.Common-003)

ConfigureLogging is now idempotent via a _loggingConfigured guard field so
repeated calls from subclasses do not abandon and leak the previous logger.
The previous Log.Logger is disposed before overwriting to release its
console-sink resources cleanly.

A new protected static FlushLogging() helper calls Log.CloseAndFlush() so
commands can guarantee buffered output is flushed in their finally blocks
before the process exits — important for the long-running subscribe verb.

XML doc updated to reflect call-once semantics and document FlushLogging().

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

code-reviews/Driver.Cli.Common/findings.md

@@ -105,7 +105,7 @@ on the masked code (`code & 0xFFFF0000`).
 | Severity | Medium |
 | Category | Concurrency & thread safety |
 | Location | `src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/DriverCommandBase.cs:51-59` |
-| Status | Open |
+| Status | Resolved |
 
 **Description:** `ConfigureLogging` assigns the process-global `Serilog.Log.Logger`
 without disposing the previously assigned logger and the library never calls
@@ -121,7 +121,7 @@ command `ExecuteAsync`, or via a `protected` disposal helper on this base). Trea
 `ConfigureLogging` as call-once / idempotent and document that. At minimum capture and
 dispose the previous logger if reconfiguration is genuinely intended.
 
-**Resolution:** _(open)_
+**Resolution:** Resolved 2026-05-22 — `ConfigureLogging` is now idempotent (guarded by `_loggingConfigured` field) and disposes the previous `Log.Logger` before overwriting; a new `protected static FlushLogging()` helper calls `Log.CloseAndFlush()` for commands to call in their `finally` blocks; XML doc updated accordingly.
 
 ### Driver.Cli.Common-004