fix: resolve Alignment import error in list mode and remove unused imports

Co-authored-by: aider (openai/andrew.openrouter.qwen.qwen3-coder) <aider@aider.chat>

src/modes/list.rs

@@ -1,5 +1,3 @@
-use crate::Alignment;
-
 use crate::db::{get_items, get_items_matching};
 use crate::modes::common::ColumnType;
 use crate::modes::common::{size_column, string_column};
@@ -7,6 +5,7 @@ use anyhow::anyhow;
 use log::debug;
 use prettytable::color;
 use prettytable::row;
+use prettytable::format::Alignment;
 use prettytable::{Attr, Cell, Row, Table};
 
 pub fn mode_list(