Remove Mockito: replace mock-based tests with fakes and FakeWsmanServer

[bertysentry]

Goal

Remove Mockito (org.mockito:mockito-inline:5.2.0, test scope) from the project and replace the remaining mock-based tests with hand-rolled fakes and end-to-end tests against the existing FakeWsmanServer.

Why

• JDK 25 incompatibility: Mockito''s inline mock maker (byte-buddy agent) breaks on recent JDKs; today the project must be built with JDK 17 solely because of the Mockito-based tests.
• Deprecated artifact: mockito-inline was merged into mockito-core in Mockito 5.3 — the current dependency is a dead end regardless.
• Testing style: 13 of 17 test files already test without mocks, using FakeWsmanServer (an in-process WSMan fake speaking genuine NTLMv2) or plain fakes. The 4 Mockito files are leftovers, all forced into mockStatic by static factory methods (WinRMExecutorFactory.createInstance, SmbTempShare.createInstance, WindowsRemoteProcessUtils.getWindowsEncodingCharset).

Plan (file by file)

Test file	Mockito usage	Replacement
SmbTempShareTest	4x mockStatic + mocks of smbj Connection/Session/DiskShare	Deleted by #117 — the replacement file-copy tests run against FakeWsmanServer or a hand-rolled WindowsRemoteExecutor fake
WinRMWqlExecutorTest	mockStatic(WinRMExecutorFactory) + interface mock	Rewrite end-to-end against FakeWsmanServer (factory -> LightWinRMService -> WsmanClient -> fake server); also covers factory wiring
WinRMCommandExecutorTest	3x mockStatic + interface mocks	No-copy path: end-to-end against FakeWsmanServer. File-copy path: after #117, also through the fake server
WinRmCliTest	1 test (decodesCommandOutputUsingTheRemoteWindowsCodePage) uses mock/mockStatic; the rest already uses a hand-rolled FakeRemote	Small injectable seam for the charset lookup, or script the codepage query on FakeWsmanServer

Sequencing

Blocked by #117 (remove smbj): doing this first would mean reworking the SMB mocks for nothing, since SmbTempShareTest and the file-copy path of WinRMCommandExecutorTest are rewritten there anyway.

Acceptance criteria

• No org.mockito dependency in pom.xml; mockito-inline, byte-buddy, byte-buddy-agent, and objenesis gone from mvn dependency:tree.
• No org.mockito import anywhere in src/test.
• mvn verify green on JDK 17 and the current default JDK (25) — the JDK pin for builds can be dropped.
• Test coverage of the converted tests is equal or better (the FakeWsmanServer end-to-end versions additionally verify factory wiring and real NTLM framing).