feat(circles): create_circle + add_member_to_circle (v0.7.0)

- acccreatefamily endpoint creates a new circle (returns numeric ID)
- accinvite endpoint invites new users by email (familyId, identifier, role, firstname)
- fw_client now detects a00.ex errors (was only checking a00.un before)
- New modules/circles.py with FamilyRoleTypeEnum constants
- SPEC.md updated with acccreatefamily, accinvite, accupdatefamily docs
- Note: circle deletion not supported by FW API (metadelete → "delete not supported")
- Note: accinvite only works for new (non-existing) FW accounts

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 (v0.6.1)
+## Features (v0.7.0)
 
 ### Read
 
@@ -29,6 +29,8 @@ MCP server for [Family Wall](https://www.familywall.com) -- read and manage your
 - `create_recipe` -- create a new recipe (name, description, ingredients, instructions, prep/cook time, serves, url); use `\n` to separate ingredient lines
 - `update_recipe` -- update any field of an existing recipe (partial update — omitted fields unchanged)
 - `delete_recipe` -- permanently delete a recipe (only own recipes)
+- `create_circle` -- create a new Family Wall circle (group); note: circles cannot be deleted via API
+- `add_member_to_circle` -- invite a person to a circle by e-mail (for new Family Wall users only; existing accounts require in-app invitation)
 
 ## Requirements