feat: add streaming content support with offset and length parameters

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

src/modes/server/common.rs

@@ -126,6 +126,21 @@ pub struct ListItemsQuery {
 pub struct ItemQuery {
     #[serde(default = "default_allow_binary")]
     pub allow_binary: bool,
+    #[serde(default)]
+    pub offset: u64,
+    #[serde(default)]
+    pub length: u64,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct ItemContentQuery {
+    pub tags: Option<String>,
+    #[serde(default = "default_allow_binary")]
+    pub allow_binary: bool,
+    #[serde(default)]
+    pub offset: u64,
+    #[serde(default)]
+    pub length: u64,
 }
 
 fn check_bearer_auth(auth_str: &str, expected_password: &str, expected_hash: &Option<String>) -> bool {