refactor: deduplicate filter plugins, extract helpers across codebase

Bug fixes:
- client: add error field to ApiResponse to avoid swallowing server errors
- args/config: fix list_format default mismatch (5 vs 7 columns)
- client: url-encode size param in set_item_size

Dedup - filter plugins:
- Extract count_option() and pattern_option() helpers, replace 7 identical options()
- Add #[derive(Clone)] to all filter structs; remove verbose clone_box() impls
- Simplify FilterChain clone() and impl Clone for Box<dyn FilterPlugin>
- Add filter_clone_box! macro for future use
- Fix doctest example missing clone_box

Dedup - server API:
- Extract spawn_body_reader() with LimitBehavior enum for body streaming
- Extract check_binary_content() helper
- Extract stream_with_offset_and_length() helper
- Extract generate_status() helper in status.rs
- Extract append_query_params() helper in client.rs

Dedup - other:
- Extract yaml_value_to_string() in meta_plugin/mod.rs
- Extract item_from_row() in db.rs
- Delete unused DisplayListItem struct

Misc:
- Remove duplicate doc comment in compression_service.rs

src/modes/list.rs

@@ -121,7 +121,7 @@ pub fn mode_list(
     table.set_header(header_cells);
 
     for item_with_meta in items_with_meta {
-        let tags: Vec<String> = item_with_meta.tags.iter().map(|t| t.name.clone()).collect();
+        let tags = item_with_meta.tag_names();
         let meta = item_with_meta.meta_as_map();
         let item = item_with_meta.item;
 
@@ -268,7 +268,7 @@ fn show_list_structured(
     let mut list_items = Vec::new();
 
     for item_with_meta in items_with_meta {
-        let tags: Vec<String> = item_with_meta.tags.iter().map(|t| t.name.clone()).collect();
+        let tags = item_with_meta.tag_names();
         let meta = item_with_meta.meta_as_map();
         let item = item_with_meta.item;
         let item_id = item.id.context("Item missing ID")?;