fix: get_categories locale filter and list-type filter (v0.4.9)

Bug 1: all 171 category locale variants were returned; now filtered by
locale parameter (default "de") → 13 German categories for shopping lists.

Bug 2: TODO lists returned 171 shopping categories because
sortingIndexByTaskList contains ALL list IDs regardless of type.
Fix: look up list's taskListType via taskgettasklists, then match against
category's taskListType. TODO lists (type=TODOS) return empty list since
all API categories are SHOPPING_LIST type.

sortingIndexByTaskList is explicitly documented as unreliable for type
filtering in both code comments and SPEC.md.

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, and tasks directly from Claude.
 
-## Features (v0.4.8)
+## Features (v0.4.9)
 
 ### Read
 
@@ -10,7 +10,7 @@ MCP server for [Family Wall](https://www.familywall.com) -- read and manage your
 - `get_members` -- list members of a circle (or all circles)
 - `get_lists` -- list all task lists (optionally filtered by circle)
 - `get_tasks` -- list tasks in a specific list
-- `get_categories` -- list categories available for a list
+- `get_categories` -- list categories available for a list (locale-filtered, default: German)
 - `get_activities` -- list recent wall activities (author resolved to display name)
 
 ### Write (with confirmation prompt)