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/domain.py

@@ -11,6 +11,7 @@ from typing import Any
 
 from .config import MAX_STORAGE_MIB, MIN_STORAGE_MIB
 from .errors import StateError, ValidationError
+from .tool_catalog import ToolSelection
 
 
 STATE_SCHEMA_VERSION = 3
@@ -55,6 +56,7 @@ class VmSpec:
     name: str | None = None
     ports: tuple[PortRule, ...] = (PortRule(22),)
     storage_mib: int = MIN_STORAGE_MIB
+    tools: tuple[ToolSelection, ...] = ()
 
 
 @dataclass(frozen=True, slots=True)