Refactor VM lifecycle management and enhance validation

- Introduced a new method `installed_kernel` in `ImageStore` to handle kernel verification and checksum validation.
- Updated `Installer` to include additional packages: `nftables` and `conntrack`.
- Refined `LifecycleService` to improve error handling and state management during VM creation, starting, stopping, and deletion.
- Enhanced port management with new methods for setting and syncing ports, including validation for port rules.
- Improved error handling in `StateStore` to raise specific `NotFoundError` and `ConflictError` exceptions.
- Updated network management to ensure proper TAP device handling and firewall integration.
- Enhanced API responses in `vms.py` to include policy status for better client-side handling.
- Added validation for VM names and ports in `validation.py` to enforce stricter rules and prevent conflicts.

uvm/server.py

@@ -8,7 +8,7 @@ import ssl
 from typing import Any
 
 from .app import Application, build_application
-from .errors import ConfigurationError, UvmError, ValidationError
+from .errors import ConfigurationError, ConflictError, NotFoundError, UvmError, ValidationError
 
 
 def create_api(application: Application | None = None, *, host: str | None = None) -> Any:
@@ -115,13 +115,12 @@ def _validate_server_settings(
 
 
 def _http_status_for(error: UvmError) -> int:
+    if isinstance(error, NotFoundError):
+        return 404
+    if isinstance(error, ConflictError):
+        return 409
     if isinstance(error, (ConfigurationError, ValidationError)):
         return 422
-    message = str(error)
-    if message.startswith("VM not found:"):
-        return 404
-    if "operation is already in progress" in message:
-        return 409
-    if "needs root" in message:
+    if "needs root" in str(error):
         return 403
     return 500