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/common.rs

@@ -446,15 +446,6 @@ pub struct DisplayItemInfo {
     pub metadata: Vec<(String, String)>,
 }
 
-/// Display data for a single list row (used by --list).
-pub struct DisplayListItem {
-    pub id: i64,
-    pub time: String,
-    pub size: String,
-    pub compression: String,
-    pub tags: Vec<String>,
-}
-
 /// Renders item detail table. Shared by local and client info modes.
 pub fn render_item_info_table(info: &DisplayItemInfo, table_config: &config::TableConfig) {
     use comfy_table::{Attribute, Cell};