feat(lists): add update_list tool (v0.7.3)

Implements taskupdatelist endpoint (verified via FW_DEBUG=1):
- Parameter 'metaId' (not 'id') identifies the list
- Partial update: only provided fields (name/color/emoji) are changed
- Reads rights.canUpdate before calling the endpoint (single session)
- System lists (canUpdate != 'true') are rejected with a clear error
- Scope derived from list metaId for secondary-circle support

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

src/mcp_familywall/__init__.py

@@ -1 +1 @@
-__version__ = "0.7.2"
+__version__ = "0.7.3"

src/mcp_familywall/server.py

@@ -1140,6 +1140,132 @@ def delete_list(list_id: str) -> str:
     )
 
 
+# ---------------------------------------------------------------------------
+# Tool: update_list
+# ---------------------------------------------------------------------------
+
+
+@mcp.tool()
+def update_list(
+    list_id: str,
+    name: str | None = None,
+    color: str | None = None,
+    emoji: str | None = None,
+) -> str:
+    """Update a task list's name, color, or emoji.
+
+    IMPORTANT: Ask the user for confirmation before calling this tool.
+
+    Performs a partial update — only the fields you provide are changed.
+    The current values for any omitted fields are preserved on the server
+    (the server keeps them; no need to fetch and re-send them).
+
+    Only user-created lists with ``rights.canUpdate="true"`` can be updated.
+    System lists are protected and this tool will refuse to update them.
+
+    Args:
+        list_id: List metaId from get_lists
+            (e.g. ``"taskList/23431854_29759623"``).
+        name: New display name (omit to keep existing).
+        color: New background colour as a hex string (e.g. ``"#E53935"``).
+            Omit to keep existing.
+        emoji: New Unicode emoji icon (e.g. ``"🧪"``).
+            Omit to keep existing.
+
+    Returns:
+        JSON with the updated list object on success, or an error message.
+    """
+    if name is None and color is None and emoji is None:
+        return "Error: At least one of 'name', 'color', or 'emoji' must be provided."
+
+    try:
+        email, password = get_credentials()
+    except RuntimeError as exc:
+        return f"Error: {exc}"
+
+    # Derive the owning circle from the list metaId (same as delete_list).
+    circle_scope = _circle_id_from_list_id(list_id)
+
+    list_obj: dict[str, Any] | None = None
+    try:
+        with FamilyWallClient() as client:
+            client.login(email, password)
+
+            # Fetch list to verify rights.canUpdate before updating.
+            get_params: dict[str, Any] = {}
+            if circle_scope:
+                get_params["scope"] = circle_scope
+            raw = client.call("taskgettasklists", get_params)
+            try:
+                raw_lists: list[dict[str, Any]] = raw["a00"]["r"]["r"]
+                if not isinstance(raw_lists, list):
+                    raw_lists = []
+            except (KeyError, TypeError):
+                raw_lists = []
+
+            list_obj = next((lst for lst in raw_lists if lst.get("metaId") == list_id), None)
+            if list_obj is None:
+                client.logout()
+                return f"Error: List '{list_id}' not found."
+
+            can_update: str | None = (list_obj.get("rights") or {}).get("canUpdate")
+            if can_update != "true":
+                client.logout()
+                return json.dumps(
+                    {
+                        "error": "System lists cannot be updated.",
+                        "id": list_id,
+                        "name": list_obj.get("name"),
+                        "hint": "Only user-created lists (rights.canUpdate=true) can be updated.",
+                    },
+                    ensure_ascii=False,
+                    indent=2,
+                )
+
+            # Build update params — only include provided fields.
+            # Verified: taskupdatelist uses 'metaId' (not 'id') as the list identifier.
+            upd_params: dict[str, Any] = {"metaId": list_id}
+            if name is not None:
+                upd_params["name"] = name
+            if color is not None:
+                upd_params["color"] = color
+            if emoji is not None:
+                upd_params["emoji"] = emoji
+
+            resp = client.call("taskupdatelist", upd_params)
+            client.logout()
+    except FamilyWallError as exc:
+        return f"Error: Family Wall API error: {exc}"
+    except Exception as exc:
+        return f"Error: Connection error: {exc}"
+
+    try:
+        updated_obj: dict[str, Any] = resp["a00"]["r"]["r"]
+        if not isinstance(updated_obj, dict) or "metaId" not in updated_obj:
+            raise TypeError("unexpected shape")
+    except (KeyError, TypeError):
+        return json.dumps(
+            {"warning": "Unexpected taskupdatelist response structure", "raw": resp},
+            ensure_ascii=False,
+            indent=2,
+        )
+
+    raw_emoji: str = updated_obj.get("emoji", "")
+    return json.dumps(
+        {
+            "updated": True,
+            "id": updated_obj.get("metaId"),
+            "name": translate_name(updated_obj.get("name", "")),
+            "type": updated_obj.get("taskListType"),
+            "emoji": raw_emoji if raw_emoji else None,
+            "color": updated_obj.get("color") or None,
+            "circle_id": updated_obj.get("familyId"),
+        },
+        ensure_ascii=False,
+        indent=2,
+    )
+
+
 # ---------------------------------------------------------------------------
 # Tool: create_circle
 # ---------------------------------------------------------------------------