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

src/trello_plugin/client.py

@@ -259,6 +259,11 @@ class TrelloClient:
             board = result["data"]
             return {"id": board["id"], "name": board.get("name", ""), "url": board.get("url", "")}
 
+        # If the error is about missing credentials, propagate that directly
+        error_msg = result.get("message", "")
+        if "TRELLO_API_KEY" in error_msg:
+            return {"success": False, "message": error_msg}
+
         # Try resolving by name
         boards_result = self.list_boards()
         if not _is_success(boards_result):  # type: ignore[arg-type]
@@ -462,6 +467,110 @@ class TrelloClient:
             },
         }
 
+    # ------------------------------------------------------------------
+    # Public API — List Management
+    # ------------------------------------------------------------------
+
+    def create_list(self, name: str, board_id: str, pos: str = "bottom") -> dict[str, Any]:
+        """Create a new list on a Trello board.
+
+        Args:
+            name: The name for the new list.
+            board_id: Board ID or name.
+            pos: Position — ``"top"``, ``"bottom"``, or a number.
+
+        Returns:
+            dict with list details on success, or an error dict.
+        """
+        resolved = self._resolve_board_id(board_id)
+        if "success" in resolved and resolved["success"] is False:
+            return resolved  # type: ignore[typeddict-item]
+
+        body: dict[str, Any] = {
+            "name": name,
+            "idBoard": resolved["id"],
+            "pos": pos,
+        }
+        result = self._post("/lists", json_body=body)
+        if _is_success(result):
+            lst = result["data"]
+            return {
+                "success": True,
+                "list": {
+                    "id": lst.get("id"),
+                    "name": lst.get("name"),
+                    "id_board": lst.get("idBoard"),
+                },
+            }
+        return {
+            "success": False,
+            "message": result.get("message", "Failed to create list."),
+        }
+
+    def rename_list(self, list_id: str, name: str) -> dict[str, Any]:
+        """Rename an existing list.
+
+        Args:
+            list_id: Trello list ID.
+            name: The new name.
+
+        Returns:
+            dict with list details on success, or an error dict.
+        """
+        result = self._put(f"/lists/{list_id}", json_body={"name": name})
+        if _is_success(result):
+            lst = result["data"]
+            return {
+                "success": True,
+                "list": {
+                    "id": lst.get("id"),
+                    "name": lst.get("name"),
+                },
+            }
+        return {
+            "success": False,
+            "message": result.get("message", "Failed to rename list."),
+        }
+
+    def archive_list(self, list_id: str) -> dict[str, Any]:
+        """Archive a list.
+
+        Args:
+            list_id: Trello list ID.
+
+        Returns:
+            dict with success message or error.
+        """
+        result = self._put(f"/lists/{list_id}", json_body={"closed": True})
+        if _is_success(result):
+            lst = result["data"]
+            list_name = lst.get("name", list_id)
+            return {"success": True, "message": f"List '{list_name}' archived."}
+        return {
+            "success": False,
+            "message": result.get("message", "Failed to archive list."),
+        }
+
+    def move_list(self, list_id: str, pos: str = "bottom") -> dict[str, Any]:
+        """Move a list to a different position on the board.
+
+        Args:
+            list_id: Trello list ID.
+            pos: Position — ``"top"``, ``"bottom"``, or a number.
+
+        Returns:
+            dict with success message or error.
+        """
+        result = self._put(f"/lists/{list_id}", json_body={"pos": pos})
+        if _is_success(result):
+            lst = result["data"]
+            list_name = lst.get("name", list_id)
+            return {"success": True, "message": f"List '{list_name}' moved."}
+        return {
+            "success": False,
+            "message": result.get("message", "Failed to move list."),
+        }
+
     @staticmethod
     def check_requirements() -> bool:
         """Check if the required environment variables are set."""