Refactor IPC and DTO structures; remove unused code and streamline message handling

- Removed unused structs and methods from `response.rs`, `usage.rs`, and `client.rs`.
- Simplified `Connection` handling in `conn.rs` to only support Unix sockets.
- Updated `IpcServer` to exclusively use Unix sockets and removed TCP handling.
- Cleaned up `editlog.rs` by removing loading and recent entry methods.
- Refactored `memory.rs` to eliminate unused functions related to lesson promotion and retrospective creation.
- Enhanced `search.rs` to support multiple search providers and improved error handling.
- Updated chat view logic to simplify message display and improve user experience.
- Removed deprecated modules and constants from various files to streamline the codebase.

src/dto/provider/response.rs

@@ -15,43 +15,3 @@ pub struct Choice {
     pub message: super::super::chat::message::ChatMessage,
     pub finish_reason: Option<String>,
 }
-
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct StreamChunk {
-    pub id: Option<String>,
-    pub model: Option<String>,
-    pub choices: Vec<StreamChoice>,
-    pub usage: Option<super::usage::Usage>,
-}
-
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct StreamChoice {
-    pub index: u32,
-    pub delta: Delta,
-    pub finish_reason: Option<String>,
-}
-
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct Delta {
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub role: Option<String>,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub content: Option<String>,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub tool_calls: Option<Vec<DeltaToolCall>>,
-}
-
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct DeltaToolCall {
-    pub index: u32,
-    pub id: Option<String>,
-    #[serde(rename = "type")]
-    pub type_: Option<String>,
-    pub function: Option<DeltaFunction>,
-}
-
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct DeltaFunction {
-    pub name: Option<String>,
-    pub arguments: Option<String>,
-}

src/dto/provider/usage.rs

@@ -10,9 +10,3 @@ pub struct Usage {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub completion_tokens_cost: Option<f64>,
 }
-
-impl Usage {
-    pub fn total(&self) -> u32 {
-        self.total_tokens.unwrap_or(0)
-    }
-}