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/client.rs

@@ -35,6 +35,18 @@ fn url_encode(s: &str) -> String {
     result
 }
 
+fn append_query_params(url: &mut String, params: &[(&str, &str)]) {
+    if !params.is_empty() {
+        url.push('?');
+        for (i, (key, value)) in params.iter().enumerate() {
+            if i > 0 {
+                url.push('&');
+            }
+            url.push_str(&format!("{}={}", url_encode(key), url_encode(value)));
+        }
+    }
+}
+
 pub struct KeepClient {
     base_url: String,
     agent: ureq::Agent,
@@ -127,15 +139,7 @@ impl KeepClient {
         params: &[(&str, &str)],
     ) -> Result<T, CoreError> {
         let mut url = self.url(path);
-        if !params.is_empty() {
-            url.push('?');
-            for (i, (key, value)) in params.iter().enumerate() {
-                if i > 0 {
-                    url.push('&');
-                }
-                url.push_str(&format!("{}={}", url_encode(key), url_encode(value)));
-            }
-        }
+        append_query_params(&mut url, params);
         let mut req = self.agent.get(&url);
         if let Some(ref auth) = self.auth_header() {
             req = req.header("Authorization", auth);
@@ -180,15 +184,7 @@ impl KeepClient {
         params: &[(&str, &str)],
     ) -> Result<ItemInfo, CoreError> {
         let mut url = self.url(path);
-        if !params.is_empty() {
-            url.push('?');
-            for (i, (key, value)) in params.iter().enumerate() {
-                if i > 0 {
-                    url.push('&');
-                }
-                url.push_str(&format!("{}={}", url_encode(key), url_encode(value)));
-            }
-        }
+        append_query_params(&mut url, params);
 
         let mut req = self.agent.post(&url);
         if let Some(ref auth) = self.auth_header() {
@@ -246,11 +242,17 @@ impl KeepClient {
         #[derive(serde::Deserialize)]
         struct ApiResponse {
             data: Option<ItemInfo>,
+            error: Option<String>,
         }
         let response: ApiResponse = self.get_json(&format!("/api/item/{id}/info"))?;
-        response
-            .data
-            .ok_or_else(|| CoreError::Other(anyhow::anyhow!("Item not found")))
+        response.data.ok_or_else(|| {
+            CoreError::Other(anyhow::anyhow!(
+                "{}",
+                response
+                    .error
+                    .unwrap_or_else(|| "Item not found".to_string())
+            ))
+        })
     }
 
     pub fn list_items(
@@ -265,6 +267,7 @@ impl KeepClient {
         #[derive(serde::Deserialize)]
         struct ApiResponse {
             data: Option<Vec<ItemInfo>>,
+            error: Option<String>,
         }
 
         let mut params: Vec<(String, String)> = Vec::new();
@@ -296,7 +299,13 @@ impl KeepClient {
             .collect();
 
         let response: ApiResponse = self.get_json_with_query("/api/item/", &param_refs)?;
-        Ok(response.data.unwrap_or_default())
+        if let Some(data) = response.data {
+            return Ok(data);
+        }
+        if let Some(err) = response.error {
+            return Err(CoreError::Other(anyhow::anyhow!("Server error: {err}")));
+        }
+        Ok(Vec::new())
     }
 
     pub fn save_item(
@@ -358,7 +367,7 @@ impl KeepClient {
         let url = format!(
             "{}?uncompressed_size={}",
             self.url(&format!("/api/item/{id}/update")),
-            size
+            url_encode(&size.to_string())
         );
         let mut req = self.agent.post(&url);
         if let Some(ref auth) = self.auth_header() {
@@ -446,15 +455,7 @@ impl KeepClient {
             .collect();
 
         let mut url = self.url("/api/export");
-        if !param_refs.is_empty() {
-            url.push('?');
-            for (i, (key, value)) in param_refs.iter().enumerate() {
-                if i > 0 {
-                    url.push('&');
-                }
-                url.push_str(&format!("{}={}", url_encode(key), url_encode(value)));
-            }
-        }
+        append_query_params(&mut url, &param_refs);
 
         let mut req = self.agent.get(&url);
         if let Some(ref auth) = self.auth_header() {