fix(circles): protect primary circle from rename in update_circle (v0.7.5)

Adds isFirstFamily check to update_circle — mirrors the same guard
already present in delete_circle. Attempting to rename the primary
circle now returns a clear error instead of silently renaming it.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/mcp_familywall/__init__.py

@@ -1 +1 @@
-__version__ = "0.7.4"
+__version__ = "0.7.5"

src/mcp_familywall/server.py

@@ -1399,6 +1399,22 @@ def update_circle(circle_id: str, name: str) -> str:
                     indent=2,
                 )
 
+            if target.get("isFirstFamily") == "true":
+                client.logout()
+                return json.dumps(
+                    {
+                        "error": "Cannot rename the primary circle.",
+                        "id": circle_id,
+                        "name": target.get("name"),
+                        "hint": (
+                            "The primary (first) circle cannot be renamed via the API. "
+                            "Use the Family Wall app settings to manage it."
+                        ),
+                    },
+                    ensure_ascii=False,
+                    indent=2,
+                )
+
             # Rename the circle.
             # Verified: accupdatefamily with scope=<circle_metaId> targets any circle,
             # both primary and secondary. The server capitalises the first letter.