App, lib, cmds: Fix mypy.explicit-override fallout

This commit adds @override decorators to approximately 300 methods
across 76 files that inherit from base classes such as AbstractCmd,
FileContext, ExecContext, Distro, SSHClient, and others.

The decorator ensures the type checker can verify that overridden
methods have compatible signatures and prevents accidental shadowing
of inherited methods without intent.

Files modified include command classes, library modules, distro
implementations, and SSH client implementations.

Assisted-by: unsloth/Qwen3.6-35B-A3B-GGUF:IQ4_NL with pi.dev v
Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/lib/ec/ssh/AsyncSSH.py

@@ -1,3 +1,4 @@
+from typing import override
 import asyncio
 import os
 import shlex
@@ -42,10 +43,12 @@ class AsyncSSH(Base):
         self.__connect_timeout = connect_timeout
         self.__conn: asyncssh.SSHClientConnection | None = None
 
+    @override
     async def _open(self) -> None:
         await super()._open()
         await self._conn
 
+    @override
     async def _close(self) -> None:
         if self.__conn is not None:
             try:
@@ -355,6 +358,7 @@ class AsyncSSH(Base):
         stdout = b''.join(stdout_parts) if stdout_parts else None
         return Result(stdout, None, exit_code, cmd = cmd)
 
+    @override
     async def _run_ssh(
         self,
         cmd: list[str],

src/python/jw/pkg/lib/ec/ssh/Exec.py

@@ -2,7 +2,7 @@ from __future__ import annotations
 
 import os
 
-from typing import TYPE_CHECKING
+from typing import override, TYPE_CHECKING
 
 from ...base import InputMode
 from ...util import run_cmd
@@ -48,6 +48,7 @@ class Exec(Base):
                 self.__askpass_orig[key] = os.getenv(key)
                 os.environ[key] = val
 
+    @override
     async def _run_ssh(
         self,
         cmd: list[str],

src/python/jw/pkg/lib/ec/ssh/Paramiko.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import TYPE_CHECKING
+from typing import override, TYPE_CHECKING
 
 # Tolerate missing paramiko imports. jw-pkg is designed to work with what it
 # finds.
@@ -52,15 +52,18 @@ class Paramiko(Base):
     def __scp(self) -> Any:
         return paramiko.SCPClient(self.__client.get_transport())
 
+    @override
     async def _open(self) -> None:
         await super()._open()
         self.__client
 
+    @override
     async def _close(self) -> None:
         if self.___client is not None:
             self.___client.close()
             self.___client = None
 
+    @override
     async def _run_ssh(
         self,
         cmd: list[str],