feat: add delete_circle tool (v0.7.2)

Implements `delete_circle(circle_id)` using the verified `adminwipefamily`
endpoint. Protects the primary circle via `isFirstFamily` check. Probe
circles family/23447370 and family/23447378 cleaned up during testing.

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

src/mcp_familywall/__init__.py

@@ -1 +1 @@
-__version__ = "0.7.1"
+__version__ = "0.7.2"

src/mcp_familywall/server.py

@@ -1289,6 +1289,95 @@ def add_member_to_circle(
     )
 
 
+# ---------------------------------------------------------------------------
+# Tool: delete_circle
+# ---------------------------------------------------------------------------
+
+
+@mcp.tool()
+def delete_circle(circle_id: str) -> str:
+    """Permanently delete a Family Wall circle (group) and all its content.
+
+    IMPORTANT: Ask the user for confirmation before calling this tool.
+
+    This action cannot be undone.  All lists, tasks, recipes, and wall posts
+    inside the circle are deleted along with it.  The primary (first) circle
+    is protected and cannot be deleted.
+
+    Args:
+        circle_id: Circle metaId from ``get_circles``
+            (e.g. ``"family/23447378"``).  Must not be the primary circle.
+
+    Returns:
+        JSON success indicator or an error message.
+    """
+    try:
+        email, password = get_credentials()
+    except RuntimeError as exc:
+        return f"Error: {exc}"
+
+    circle_name: str = circle_id
+    try:
+        with FamilyWallClient() as client:
+            client.login(email, password)
+
+            # Fetch the circle list to verify the target exists and is not primary.
+            circles_data = client.call("famlistfamily")
+            try:
+                raw_circles: list[dict[str, Any]] = circles_data["a00"]["r"]["r"]
+                if not isinstance(raw_circles, list):
+                    raise TypeError("a00.r.r is not a list")
+            except (KeyError, TypeError):
+                client.logout()
+                return "Error: Unexpected famlistfamily response structure."
+
+            target = next((c for c in raw_circles if c.get("metaId") == circle_id), None)
+            if target is None:
+                client.logout()
+                available = [c.get("metaId") for c in raw_circles]
+                return json.dumps(
+                    {
+                        "error": f"Circle not found: {circle_id!r}",
+                        "available_circles": available,
+                    },
+                    ensure_ascii=False,
+                    indent=2,
+                )
+
+            if target.get("isFirstFamily") == "true":
+                client.logout()
+                return json.dumps(
+                    {
+                        "error": "Cannot delete the primary circle.",
+                        "id": circle_id,
+                        "name": target.get("name"),
+                        "hint": (
+                            "The primary (first) circle cannot be deleted via the API. "
+                            "Use the Family Wall app settings to manage it."
+                        ),
+                    },
+                    ensure_ascii=False,
+                    indent=2,
+                )
+
+            circle_name = target.get("name", circle_id)
+
+            # Verified — delete in the same session.
+            # adminwipefamily uses scope=<circle_metaId> and returns a00.r.r="true".
+            client.call("adminwipefamily", {"scope": circle_id})
+            client.logout()
+    except FamilyWallError as exc:
+        return f"Error: Family Wall API error: {exc}"
+    except Exception as exc:
+        return f"Error: Connection error: {exc}"
+
+    return json.dumps(
+        {"deleted": True, "id": circle_id, "name": circle_name},
+        ensure_ascii=False,
+        indent=2,
+    )
+
+
 # ---------------------------------------------------------------------------
 # Tool: like_post
 # ---------------------------------------------------------------------------