Add missing frontend and backend files

backend/src/media_library_viewer_api/clients/local.py

@@ -0,0 +1,60 @@
+"""Local command execution helpers.
+
+These mirror the remote SSH helpers but execute commands on the API host
+itself. They are used for the built-in local monitoring machine.
+"""
+
+from __future__ import annotations
+
+import logging
+import posixpath
+import subprocess
+from dataclasses import dataclass
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class CommandResult:
+    """Plain result object returned by local command execution."""
+
+    command: str
+    exit_status: int
+    stdout: str
+    stderr: str
+
+
+class LocalCommandClient:
+    """Execute the same POSIX shell snippets used by the SSH client locally."""
+
+    def __init__(self, timeout: int = 20):
+        self.timeout = timeout
+
+    def run(self, command: str, timeout: int | None = None) -> CommandResult:
+        shell_command = ["/bin/sh", "-c", command]
+        logger.debug("Local run timeout=%s command=%s", timeout or self.timeout, command)
+        proc = subprocess.run(
+            shell_command,
+            capture_output=True,
+            text=True,
+            timeout=timeout or self.timeout,
+        )
+        result = CommandResult(
+            command=command,
+            exit_status=proc.returncode,
+            stdout=proc.stdout,
+            stderr=proc.stderr,
+        )
+        if result.exit_status == 0:
+            logger.debug("Local command ok exit_status=%s", result.exit_status)
+        else:
+            logger.warning(
+                "Local command failed exit_status=%s stderr=%s",
+                result.exit_status,
+                result.stderr.strip() or result.stdout.strip(),
+            )
+        return result
+
+    @staticmethod
+    def join(parent: str, child: str) -> str:
+        return posixpath.normpath(posixpath.join(parent, child))