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>

README.md

@@ -2,7 +2,7 @@
 
 MCP server for [Family Wall](https://www.familywall.com) -- read and manage your family's circles, lists, tasks, and recipes directly from Claude.
 
-## Features (v0.7.2)
+## Features (v0.7.3)
 
 ### Read
 
@@ -22,6 +22,7 @@ MCP server for [Family Wall](https://www.familywall.com) -- read and manage your
 - `toggle_task` -- mark a task complete or reopen it
 - `delete_task` -- permanently delete a task
 - `create_list` -- create a new task list (SHOPPING_LIST or TODOS; optional `emoji`, `color`, and `circle_id` to target a specific circle)
+- `update_list` -- rename a list or change its emoji/color (partial update — omitted fields unchanged; system lists are protected)
 - `delete_list` -- permanently delete a list and all its tasks (system lists are protected)
 - `create_category` -- create a custom category for a shopping list (with optional icon)
 - `delete_category` -- delete a custom category (system categories are protected)