feat: implement resource resizing for VMs with storage management

- Added KnownHostsManager to handle cleanup of SSH known_hosts entries upon VM deletion.
- Introduced disk_size_bytes method in ImageStore to read logical disk capacity.
- Enhanced LifecycleService to manage VM resource resizing, including CPU, RAM, and storage.
- Updated application configuration to support known_hosts_files for SSH management.
- Modified dashboard to include resource resizing options in the UI.
- Improved error handling and validation for resource inputs in the dashboard.
- Removed obsolete .pyc files from the repository.

uvm/config.py

@@ -40,6 +40,7 @@ class Settings:
     api_token: str | None = None
     api_tls_cert: Path | None = None
     api_tls_key: Path | None = None
+    known_hosts_files: tuple[Path, ...] | None = None
     api_timeout_s: float = 2.0
     api_socket_timeout_s: float = 5.0
     terminate_timeout_s: float = 5.0
@@ -66,6 +67,8 @@ class Settings:
             raise ConfigurationError("gateway must be a usable host address")
         if len(self.bridge) > 15:
             raise ConfigurationError("bridge name must be 15 characters or fewer")
+        if self.known_hosts_files is not None and any(not path.is_absolute() for path in self.known_hosts_files):
+            raise ConfigurationError("UVM_KNOWN_HOSTS_FILES must contain absolute file paths")
         if self.api_token is not None:
             if not self.api_token or not all(33 <= ord(character) <= 126 for character in self.api_token):
                 raise ConfigurationError(
@@ -148,6 +151,7 @@ class Settings:
             api_token=_optional_environment_value("UVM_API_TOKEN"),
             api_tls_cert=_optional_environment_path("UVM_API_TLS_CERT"),
             api_tls_key=_optional_environment_path("UVM_API_TLS_KEY"),
+            known_hosts_files=_known_hosts_environment_paths(),
         )
 
 
@@ -161,6 +165,16 @@ def _optional_environment_path(name: str) -> Path | None:
     return Path(value).expanduser() if value else None
 
 
+def _known_hosts_environment_paths() -> tuple[Path, ...] | None:
+    value = _optional_environment_value("UVM_KNOWN_HOSTS_FILES")
+    if value is None:
+        return None
+    parts = value.split(os.pathsep)
+    if any(not part for part in parts):
+        raise ConfigurationError("UVM_KNOWN_HOSTS_FILES must be a colon-separated list of file paths")
+    return tuple(Path(part).expanduser() for part in parts)
+
+
 def _boolean_environment_value(name: str, *, default: bool) -> bool:
     value = os.environ.get(name)
     if value is None: