feat(cloud): add edge host enrollment

apps/device-host-agent/host_agent/config.py

@@ -2,7 +2,8 @@ from __future__ import annotations
 
 import os
 from collections.abc import Mapping
-from dataclasses import dataclass
+from dataclasses import dataclass, field
+from pathlib import Path
 from urllib.parse import urlparse
 
 
@@ -13,8 +14,12 @@ class HostAgentConfigurationError(ValueError):
 @dataclass(frozen=True)
 class HostAgentConfig:
     control_plane_url: str
-    host_id: str
-    token: str
+    host_id: str = ""
+    token: str = field(default="", repr=False)
+    enrollment_token: str = field(default="", repr=False)
+    identity_path: Path = Path("tasks/host_identity.json")
+    enrollment_managed: bool = False
+    display_name: str | None = None
     heartbeat_interval_seconds: float = 30.0
     poll_timeout_seconds: float = 20.0
     retry_backoff_seconds: float = 1.0
@@ -41,16 +46,29 @@ def load_host_agent_config(
         )
 
     host_id = values.get("HOST_AGENT_HOST_ID", "").strip()
-    if not host_id:
-        raise HostAgentConfigurationError("HOST_AGENT_HOST_ID is required")
     token = values.get("HOST_AGENT_TOKEN", "").strip()
-    if not token:
-        raise HostAgentConfigurationError("HOST_AGENT_TOKEN is required")
+    if bool(host_id) != bool(token):
+        raise HostAgentConfigurationError(
+            "HOST_AGENT_HOST_ID and HOST_AGENT_TOKEN must be configured together"
+        )
+    enrollment_token = values.get("HOST_AGENT_ENROLLMENT_TOKEN", "").strip()
+    identity_path = Path(
+        values.get("HOST_AGENT_IDENTITY_PATH", "tasks/host_identity.json").strip()
+    )
+    if not host_id and not enrollment_token and not identity_path.is_file():
+        raise HostAgentConfigurationError(
+            "explicit Host credentials, an enrollment token, or existing identity state "
+            "is required"
+        )
 
     config = HostAgentConfig(
         control_plane_url=control_plane_url,
         host_id=host_id,
         token=token,
+        enrollment_token=enrollment_token,
+        identity_path=identity_path,
+        enrollment_managed=not bool(host_id),
+        display_name=values.get("HOST_AGENT_DISPLAY_NAME") or None,
         heartbeat_interval_seconds=_positive_float(
             values,
             "HOST_AGENT_HEARTBEAT_INTERVAL_SECONDS",