feat: implement Trello list management

Add 4 list management tools extending the Trello client:
- trello_create_list — create a new list on a board
- trello_rename_list — rename an existing list
- trello_archive_list — archive a list
- trello_move_list — move a list to a new position

Also update the auth spec doc to reflect the PR #5 review fixes
(TypedDict contracts, updated disconnect message).

Issue: #3

docs/backend/trello-auth-spec.md

@@ -64,7 +64,9 @@ Fetches and returns all Trello boards accessible to the authenticated user.
 
 ### 3. `trello_disconnect`
 
-Clears the stored credentials from memory. Note: this does not revoke the Trello token — the user must invalidate it via Trello's settings if needed.
+Clears the stored credentials from memory. Since credentials are stored in environment variables, the next tool call will automatically re-read them and reconnect. To fully disconnect, also unset ``TRELLO_API_KEY`` and ``TRELLO_TOKEN`` from the Hermes profile config.
+
+Note: this does NOT revoke the Trello token — the user must invalidate it via Trello's settings if needed.
 
 **Parameters:** None
 
@@ -72,7 +74,7 @@ Clears the stored credentials from memory. Note: this does not revoke the Trello
 ```json
 {
   "success": true,
-  "message": "Trello credentials cleared. Set TRELLO_API_KEY and TRELLO_TOKEN again to reconnect."
+  "message": "Trello credentials cleared from memory. Next tool call will re-read TRELLO_API_KEY and TRELLO_TOKEN from environment and reconnect automatically."
 }
 ```
 
@@ -82,6 +84,9 @@ Clears the stored credentials from memory. Note: this does not revoke the Trello
 
 ```python
 class TrelloClient:
+    api_key: str
+    token: str
+
     def __init__(self, api_key: str | None = None, token: str | None = None)
 
     def verify_credentials(self) -> dict
@@ -89,6 +94,8 @@ class TrelloClient:
     def disconnect(self) -> dict
 ```
 
+The client uses `TypedDict` response contracts (`SuccessResponse`/`ErrorResponse`) with a `TypeGuard` helper `_is_success()` for type-safe narrowing. Internal helpers include `_request()`, `_get()`, `_post()`, `_put()`, `_check_credentials()`, and `_handle_http_error()`.
+
 ### Trello API Endpoints Used
 
 | Purpose | Method | Endpoint | Docs |