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.

tests/test_tool_lifecycle.py

@@ -0,0 +1,57 @@
+from __future__ import annotations
+
+from unittest.mock import Mock
+
+from tests.test_lifecycle import LifecycleTestCase
+from uvm.errors import ConflictError, NotFoundError, UvmError, ValidationError
+from uvm.tool_catalog import ToolSelection
+
+
+class ToolLifecycleTests(LifecycleTestCase):
+    def test_create_persists_tool_intent_before_boot(self):
+        def configure(config):
+            vm_id = next(iter(self.store.load().vms))
+            jobs = self.service._tool_store._read(vm_id)["jobs"]
+            self.assertEqual(jobs[0]["selections"], [{"id": "python", "version": "3.12"}])
+            self.assertEqual(jobs[0]["status"], "queued")
+        original = self.service._client_factory
+        def client(socket, timeout):
+            result = original(socket, timeout)
+            result.configure_and_start = configure
+            return result
+        self.service._client_factory = client
+        vm = self.create_vm(tools=(ToolSelection("python", "3.12"),))
+        self.assertEqual(vm.status, "running")
+        self.assertEqual(self.service._tool_store.read(vm.id)["jobs"][0]["source"], "create")
+
+    def test_invalid_tools_fail_before_reserving_a_vm_and_failed_boot_removes_intent(self):
+        with self.assertRaises(ValidationError):
+            self.create_vm(tools=({"id": "invalid"},))
+        self.assertEqual(self.store.load().vms, {})
+        self.host.failures["client.configure", None] = UvmError("failed boot")
+        with self.assertRaises(UvmError):
+            self.create_vm(tools=(ToolSelection("git"),))
+        self.assertEqual(list(self.settings.vms_dir.iterdir()), [])
+
+    def test_stopped_installation_starts_only_when_requested_and_aliases_are_rejected(self):
+        vm = self.create_vm(name="worker")
+        self.service.stop(vm.id)
+        for alias in (vm.name, vm.guest_ip):
+            with self.assertRaises(NotFoundError):
+                self.service.queue_tools(alias, [ToolSelection("git")], start_if_stopped=True)
+        with self.assertRaises(ConflictError):
+            self.service.queue_tools(vm.id, [ToolSelection("git")])
+        job = self.service.queue_tools(vm.id, [ToolSelection("git")], start_if_stopped=True)
+        self.assertEqual(self.store.get(vm.id).status, "stopped")
+        ready = self.service.prepare_tool_install(vm.id, start_if_stopped=job["start_if_stopped"])
+        self.assertEqual(ready.status, "running")
+        self.assertEqual(ready.guest_ip, vm.guest_ip)
+
+    def test_a_tool_step_cannot_reconnect_to_a_restarted_vm(self):
+        vm = self.create_vm()
+        identity = vm.pid, vm.process_start_time, vm.boot_id
+        self.service.restart(vm.id)
+        self.service._guest_connector = Mock()
+        with self.assertRaisesRegex(ConflictError, "restarted"):
+            self.service.execute(vm.id, "id", expected_identity=identity)
+        self.service._guest_connector.assert_not_called()