docs: align versions and update update-service docs

docs/update-api.md

@@ -1,4 +1,4 @@
-ID: DOC_000006 | Version: 0.1.0 | Status: Draft
+ID: DOC_000006 | Version: 0.2.1 | Status: Draft
 By: Codex (GPT-5)
 
 # Update API (Kiddo Backend)
@@ -8,6 +8,16 @@ Definiert interne API-Endpunkte fuer Update-Status, Check, Apply, Rollback und L
 
 ## Endpoints
 
+### POST /update/enroll
+Body (optional):
+```json
+{ "enroll_token": "<one-time-token>" }
+```
+Antwort:
+```json
+{ "enrolled": true, "message": "Enrollment successful" }
+```
+
 ### GET /update/status
 Antwort:
 ```json
@@ -15,7 +25,8 @@ Antwort:
   "current_version": "0.1.2",
   "last_status": "success|failed|unknown",
   "last_error": "<optional>",
-  "last_timestamp": "2025-12-28T12:34:56Z"
+  "last_timestamp": "2025-12-28T12:34:56Z",
+  "enrolled": true
 }
 ```
 
@@ -51,10 +62,18 @@ Antwort:
 Antwort:
 ```json
 [
-  {"timestamp":"2025-12-28T12:34:56Z","status":"success","message":"updated to 0.1.2"}
+  {
+    "timestamp": "2025-12-28T12:34:56Z",
+    "status": "success",
+    "message": "updated to 0.1.2",
+    "version": "0.1.2",
+    "device_id": "kiddo-001",
+    "error": null
+  }
 ]
 ```
 
 ## Notes
-- Alle Endpunkte erfordern Auth (Session/Bearer).
+- Alle Endpunkte erfordern Auth (Session-Cookie oder `Authorization: Bearer <token>`).
 - Apply/Rollback starten async; UI pollt /update/status.
+- `/update/enroll` speichert das Update-Token lokal (siehe `SKD_UPDATE_TOKEN_FILE`).