feat: implement batch queries for improved list performance

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

src/db.rs

@@ -443,3 +443,66 @@ pub fn get_item_meta_value(conn: &Connection, item: &Item, name: String) -> Resu
         None => Ok(None),
     }
 }
+
+pub fn get_tags_for_items(conn: &Connection, item_ids: &[i64]) -> Result<std::collections::HashMap<i64, Vec<Tag>>> {
+    debug!("DB: Getting tags for items: {:?}", item_ids);
+    
+    if item_ids.is_empty() {
+        return Ok(std::collections::HashMap::new());
+    }
+    
+    // Create placeholders for the IN clause
+    let placeholders: Vec<String> = item_ids.iter().map(|_| "?".to_string()).collect();
+    let placeholders_str = placeholders.join(",");
+    
+    let sql = format!("SELECT id, name FROM tags WHERE id IN ({}) ORDER BY id ASC, name ASC", placeholders_str);
+    
+    let mut statement = conn
+        .prepare_cached(&sql)
+        .context("Problem preparing SQL statement")?;
+    
+    let mut rows = statement.query(rusqlite::params_from_iter(item_ids))?;
+    
+    let mut tags_map: std::collections::HashMap<i64, Vec<Tag>> = std::collections::HashMap::new();
+    
+    while let Some(row) = rows.next()? {
+        let id: i64 = row.get(0)?;
+        let name: String = row.get(1)?;
+        
+        tags_map.entry(id).or_insert_with(Vec::new).push(Tag { id, name });
+    }
+    
+    Ok(tags_map)
+}
+
+pub fn get_meta_for_items(conn: &Connection, item_ids: &[i64]) -> Result<std::collections::HashMap<i64, std::collections::HashMap<String, String>>> {
+    debug!("DB: Getting meta for items: {:?}", item_ids);
+    
+    if item_ids.is_empty() {
+        return Ok(std::collections::HashMap::new());
+    }
+    
+    // Create placeholders for the IN clause
+    let placeholders: Vec<String> = item_ids.iter().map(|_| "?".to_string()).collect();
+    let placeholders_str = placeholders.join(",");
+    
+    let sql = format!("SELECT id, name, value FROM metas WHERE id IN ({}) ORDER BY id ASC, name ASC", placeholders_str);
+    
+    let mut statement = conn
+        .prepare_cached(&sql)
+        .context("Problem preparing SQL statement")?;
+    
+    let mut rows = statement.query(rusqlite::params_from_iter(item_ids))?;
+    
+    let mut meta_map: std::collections::HashMap<i64, std::collections::HashMap<String, String>> = std::collections::HashMap::new();
+    
+    while let Some(row) = rows.next()? {
+        let id: i64 = row.get(0)?;
+        let name: String = row.get(1)?;
+        let value: String = row.get(2)?;
+        
+        meta_map.entry(id).or_insert_with(std::collections::HashMap::new).insert(name, value);
+    }
+    
+    Ok(meta_map)
+}