Implement guest tool installation and management system

- Added `guest_tools.py` for standalone tool installer functionality.
- Introduced `ToolJobStore` in `tool_store.py` to manage per-VM tool job records.
- Created `ToolService` in `tools.py` for background installation workers using the guest execution channel.
- Enhanced `LifecycleService` in `lifecycle.py` to support tool installation queuing and preparation.
- Updated `guest_exec.py` to handle connection shutdown gracefully.
- Added validation and normalization functions for tool specifications.
- Implemented logging and error handling for tool installation processes.
- Ensured compatibility with Ubuntu 22.04 and ARM64/x86_64 architectures.

uvm/guest_exec.py

@@ -111,4 +111,10 @@ class GuestSession:
             ) from error
 
     def close(self) -> None:
+        # Wake a thread waiting for a long-running tool command on server shutdown.
+        # The guest still owns its bounded command and package-manager cleanup.
+        try:
+            self._connection.shutdown(socket.SHUT_RDWR)
+        except OSError:
+            pass
         self._connection.close()